diff --git a/codex-rs/cli/src/debug_sandbox.rs b/codex-rs/cli/src/debug_sandbox.rs
index e5cccfc53..f64c45c73 100644
--- a/codex-rs/cli/src/debug_sandbox.rs
+++ b/codex-rs/cli/src/debug_sandbox.rs
@@ -164,14 +164,17 @@ async fn run_command_under_sandbox(
             let res = tokio::task::spawn_blocking(move || {
                 if use_elevated {
                     run_windows_sandbox_capture_elevated(
-                        policy_str.as_str(),
-                        &sandbox_cwd,
-                        base_dir.as_path(),
-                        command_vec,
-                        &cwd_clone,
-                        env_map,
-                        /*timeout_ms*/ None,
-                        config.permissions.windows_sandbox_private_desktop,
+                        codex_windows_sandbox::ElevatedSandboxCaptureRequest {
+                            policy_json_or_preset: policy_str.as_str(),
+                            sandbox_policy_cwd: &sandbox_cwd,
+                            codex_home: base_dir.as_path(),
+                            command: command_vec,
+                            cwd: &cwd_clone,
+                            env_map,
+                            timeout_ms: None,
+                            use_private_desktop: config.permissions.windows_sandbox_private_desktop,
+                            proxy_enforced: false,
+                        },
                     )
                 } else {
                     run_windows_sandbox_capture(
diff --git a/codex-rs/core/src/exec.rs b/codex-rs/core/src/exec.rs
index 11d8600ba..fde8782f0 100644
--- a/codex-rs/core/src/exec.rs
+++ b/codex-rs/core/src/exec.rs
@@ -478,7 +478,11 @@ async fn exec_windows_sandbox(
     })?;
     let command_path = command.first().cloned();
     let sandbox_level = windows_sandbox_level;
-    let use_elevated = matches!(sandbox_level, WindowsSandboxLevel::Elevated);
+    let proxy_enforced = network.is_some();
+    // Windows firewall enforcement is tied to the logon-user sandbox identities, so
+    // proxy-enforced sessions must use that backend even when the configured mode is
+    // the default restricted-token sandbox.
+    let use_elevated = proxy_enforced || matches!(sandbox_level, WindowsSandboxLevel::Elevated);
     let additional_deny_write_paths = windows_restricted_token_filesystem_overlay
         .map(|overlay| {
             overlay
@@ -491,14 +495,17 @@ async fn exec_windows_sandbox(
     let spawn_res = tokio::task::spawn_blocking(move || {
         if use_elevated {
             run_windows_sandbox_capture_elevated(
-                policy_str.as_str(),
-                &sandbox_cwd,
-                codex_home.as_ref(),
-                command,
-                &cwd,
-                env,
-                timeout_ms,
-                windows_sandbox_private_desktop,
+                codex_windows_sandbox::ElevatedSandboxCaptureRequest {
+                    policy_json_or_preset: policy_str.as_str(),
+                    sandbox_policy_cwd: &sandbox_cwd,
+                    codex_home: codex_home.as_ref(),
+                    command,
+                    cwd: &cwd,
+                    env_map: env,
+                    timeout_ms,
+                    use_private_desktop: windows_sandbox_private_desktop,
+                    proxy_enforced,
+                },
             )
         } else {
             run_windows_sandbox_capture_with_extra_deny_write_paths(
diff --git a/codex-rs/core/src/windows_sandbox.rs b/codex-rs/core/src/windows_sandbox.rs
index 1fdf3ee33..ee3a040a6 100644
--- a/codex-rs/core/src/windows_sandbox.rs
+++ b/codex-rs/core/src/windows_sandbox.rs
@@ -180,13 +180,15 @@ pub fn run_elevated_setup(
     codex_home: &Path,
 ) -> anyhow::Result<()> {
     codex_windows_sandbox::run_elevated_setup(
-        policy,
-        policy_cwd,
-        command_cwd,
-        env_map,
-        codex_home,
-        /*read_roots_override*/ None,
-        /*write_roots_override*/ None,
+        codex_windows_sandbox::SandboxSetupRequest {
+            policy,
+            policy_cwd,
+            command_cwd,
+            env_map,
+            codex_home,
+            proxy_enforced: false,
+        },
+        codex_windows_sandbox::SetupRootOverrides::default(),
     )
 }
 
@@ -234,6 +236,7 @@ pub fn run_setup_refresh_with_extra_read_roots(
         env_map,
         codex_home,
         extra_read_roots,
+        /*proxy_enforced*/ false,
     )
 }
 
diff --git a/codex-rs/network-proxy/src/proxy.rs b/codex-rs/network-proxy/src/proxy.rs
index 8f596f684..3eecef3ee 100644
--- a/codex-rs/network-proxy/src/proxy.rs
+++ b/codex-rs/network-proxy/src/proxy.rs
@@ -51,6 +51,43 @@ impl ReservedListeners {
     }
 }
 
+struct ReservedListenerSet {
+    http_listener: StdTcpListener,
+    socks_listener: Option<StdTcpListener>,
+}
+
+impl ReservedListenerSet {
+    fn new(http_listener: StdTcpListener, socks_listener: Option<StdTcpListener>) -> Self {
+        Self {
+            http_listener,
+            socks_listener,
+        }
+    }
+
+    fn http_addr(&self) -> Result<SocketAddr> {
+        self.http_listener
+            .local_addr()
+            .context("failed to read reserved HTTP proxy address")
+    }
+
+    fn socks_addr(&self, default_addr: SocketAddr) -> Result<SocketAddr> {
+        self.socks_listener
+            .as_ref()
+            .map_or(Ok(default_addr), |listener| {
+                listener
+                    .local_addr()
+                    .context("failed to read reserved SOCKS5 proxy address")
+            })
+    }
+
+    fn into_reserved_listeners(self) -> Arc<ReservedListeners> {
+        Arc::new(ReservedListeners::new(
+            self.http_listener,
+            self.socks_listener,
+        ))
+    }
+}
+
 #[derive(Clone)]
 pub struct NetworkProxyBuilder {
     state: Option<Arc<NetworkProxyState>>,
@@ -134,38 +171,41 @@ impl NetworkProxyBuilder {
             .set_blocked_request_observer(self.blocked_request_observer.clone())
             .await;
         let current_cfg = state.current_cfg().await?;
-        let (requested_http_addr, requested_socks_addr, reserved_listeners) =
-            if self.managed_by_codex {
-                let runtime = config::resolve_runtime(&current_cfg)?;
-                let (http_listener, socks_listener) =
-                    reserve_loopback_ephemeral_listeners(current_cfg.network.enable_socks5)
-                        .context("reserve managed loopback proxy listeners")?;
-                let http_addr = http_listener
-                    .local_addr()
-                    .context("failed to read reserved HTTP proxy address")?;
-                let socks_addr = if let Some(socks_listener) = socks_listener.as_ref() {
-                    socks_listener
-                        .local_addr()
-                        .context("failed to read reserved SOCKS5 proxy address")?
-                } else {
-                    runtime.socks_addr
-                };
-                (
-                    http_addr,
-                    socks_addr,
-                    Some(Arc::new(ReservedListeners::new(
-                        http_listener,
-                        socks_listener,
-                    ))),
-                )
-            } else {
-                let runtime = config::resolve_runtime(&current_cfg)?;
-                (
-                    self.http_addr.unwrap_or(runtime.http_addr),
-                    self.socks_addr.unwrap_or(runtime.socks_addr),
-                    None,
-                )
-            };
+        let (requested_http_addr, requested_socks_addr, reserved_listeners) = if self
+            .managed_by_codex
+        {
+            let runtime = config::resolve_runtime(&current_cfg)?;
+            #[cfg(target_os = "windows")]
+            let (managed_http_addr, managed_socks_addr) = config::clamp_bind_addrs(
+                runtime.http_addr,
+                runtime.socks_addr,
+                &current_cfg.network,
+            );
+            #[cfg(target_os = "windows")]
+            let reserved = reserve_windows_managed_listeners(
+                managed_http_addr,
+                managed_socks_addr,
+                current_cfg.network.enable_socks5,
+            )
+            .context("reserve managed loopback proxy listeners")?;
+            #[cfg(not(target_os = "windows"))]
+            let reserved = reserve_loopback_ephemeral_listeners(current_cfg.network.enable_socks5)
+                .context("reserve managed loopback proxy listeners")?;
+            let http_addr = reserved.http_addr()?;
+            let socks_addr = reserved.socks_addr(runtime.socks_addr)?;
+            (
+                http_addr,
+                socks_addr,
+                Some(reserved.into_reserved_listeners()),
+            )
+        } else {
+            let runtime = config::resolve_runtime(&current_cfg)?;
+            (
+                self.http_addr.unwrap_or(runtime.http_addr),
+                self.socks_addr.unwrap_or(runtime.socks_addr),
+                None,
+            )
+        };
 
         // Reapply bind clamping for caller overrides so unix-socket proxying stays loopback-only.
         let (http_addr, socks_addr) = config::clamp_bind_addrs(
@@ -192,7 +232,7 @@ impl NetworkProxyBuilder {
 
 fn reserve_loopback_ephemeral_listeners(
     reserve_socks_listener: bool,
-) -> Result<(StdTcpListener, Option<StdTcpListener>)> {
+) -> Result<ReservedListenerSet> {
     let http_listener =
         reserve_loopback_ephemeral_listener().context("reserve HTTP proxy listener")?;
     let socks_listener = if reserve_socks_listener {
@@ -200,7 +240,53 @@ fn reserve_loopback_ephemeral_listeners(
     } else {
         None
     };
-    Ok((http_listener, socks_listener))
+    Ok(ReservedListenerSet::new(http_listener, socks_listener))
+}
+
+#[cfg(target_os = "windows")]
+fn reserve_windows_managed_listeners(
+    http_addr: SocketAddr,
+    socks_addr: SocketAddr,
+    reserve_socks_listener: bool,
+) -> Result<ReservedListenerSet> {
+    let http_addr = windows_managed_loopback_addr(http_addr);
+    let socks_addr = windows_managed_loopback_addr(socks_addr);
+
+    match try_reserve_windows_managed_listeners(http_addr, socks_addr, reserve_socks_listener) {
+        Ok(listeners) => Ok(listeners),
+        Err(err) if err.kind() == std::io::ErrorKind::AddrInUse => {
+            warn!("managed Windows proxy ports are busy; falling back to ephemeral loopback ports");
+            reserve_loopback_ephemeral_listeners(reserve_socks_listener)
+                .context("reserve fallback loopback proxy listeners")
+        }
+        Err(err) => Err(err).context("reserve Windows managed proxy listeners"),
+    }
+}
+
+#[cfg(target_os = "windows")]
+fn try_reserve_windows_managed_listeners(
+    http_addr: SocketAddr,
+    socks_addr: SocketAddr,
+    reserve_socks_listener: bool,
+) -> std::io::Result<ReservedListenerSet> {
+    let http_listener = StdTcpListener::bind(http_addr)?;
+    let socks_listener = if reserve_socks_listener {
+        Some(StdTcpListener::bind(socks_addr)?)
+    } else {
+        None
+    };
+    Ok(ReservedListenerSet::new(http_listener, socks_listener))
+}
+
+#[cfg(target_os = "windows")]
+fn windows_managed_loopback_addr(addr: SocketAddr) -> SocketAddr {
+    if !addr.ip().is_loopback() {
+        warn!(
+            "managed Windows proxies must bind to loopback; clamping {addr} to 127.0.0.1:{}",
+            addr.port()
+        );
+    }
+    SocketAddr::from(([127, 0, 0, 1], addr.port()))
 }
 
 fn reserve_loopback_ephemeral_listener() -> Result<StdTcpListener> {
@@ -570,10 +656,12 @@ mod tests {
     use std::net::Ipv4Addr;
 
     #[tokio::test]
-    async fn managed_proxy_builder_uses_loopback_ephemeral_ports() {
-        let state = Arc::new(network_proxy_state_for_policy(
-            NetworkProxySettings::default(),
-        ));
+    async fn managed_proxy_builder_uses_loopback_ports() {
+        let state = Arc::new(network_proxy_state_for_policy(NetworkProxySettings {
+            proxy_url: "http://127.0.0.1:43128".to_string(),
+            socks_url: "http://127.0.0.1:48081".to_string(),
+            ..NetworkProxySettings::default()
+        }));
         let proxy = match NetworkProxy::builder().state(state).build().await {
             Ok(proxy) => proxy,
             Err(err) => {
@@ -589,8 +677,22 @@ mod tests {
 
         assert!(proxy.http_addr.ip().is_loopback());
         assert!(proxy.socks_addr.ip().is_loopback());
-        assert_ne!(proxy.http_addr.port(), 0);
-        assert_ne!(proxy.socks_addr.port(), 0);
+        #[cfg(target_os = "windows")]
+        {
+            assert_eq!(
+                proxy.http_addr,
+                "127.0.0.1:43128".parse::<SocketAddr>().unwrap()
+            );
+            assert_eq!(
+                proxy.socks_addr,
+                "127.0.0.1:48081".parse::<SocketAddr>().unwrap()
+            );
+        }
+        #[cfg(not(target_os = "windows"))]
+        {
+            assert_ne!(proxy.http_addr.port(), 0);
+            assert_ne!(proxy.socks_addr.port(), 0);
+        }
     }
 
     #[tokio::test]
@@ -622,6 +724,7 @@ mod tests {
     async fn managed_proxy_builder_does_not_reserve_socks_listener_when_disabled() {
         let settings = NetworkProxySettings {
             enable_socks5: false,
+            proxy_url: "http://127.0.0.1:43128".to_string(),
             socks_url: "http://127.0.0.1:43129".to_string(),
             ..NetworkProxySettings::default()
         };
@@ -640,6 +743,7 @@ mod tests {
         };
 
         assert!(proxy.http_addr.ip().is_loopback());
+        assert_ne!(proxy.http_addr.port(), 0);
         assert_eq!(
             proxy.socks_addr,
             "127.0.0.1:43129".parse::<SocketAddr>().unwrap()
@@ -654,6 +758,47 @@ mod tests {
         );
     }
 
+    #[cfg(target_os = "windows")]
+    #[test]
+    fn windows_managed_loopback_addr_clamps_non_loopback_inputs() {
+        assert_eq!(
+            windows_managed_loopback_addr("0.0.0.0:3128".parse::<SocketAddr>().unwrap()),
+            "127.0.0.1:3128".parse::<SocketAddr>().unwrap()
+        );
+        assert_eq!(
+            windows_managed_loopback_addr("[::]:8081".parse::<SocketAddr>().unwrap()),
+            "127.0.0.1:8081".parse::<SocketAddr>().unwrap()
+        );
+    }
+
+    #[cfg(target_os = "windows")]
+    #[test]
+    fn reserve_windows_managed_listeners_falls_back_when_http_port_is_busy() {
+        let occupied = StdTcpListener::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
+        let busy_port = occupied.local_addr().unwrap().port();
+
+        let reserved = reserve_windows_managed_listeners(
+            SocketAddr::from(([127, 0, 0, 1], busy_port)),
+            SocketAddr::from(([127, 0, 0, 1], 48081)),
+            false,
+        )
+        .unwrap();
+
+        assert!(reserved.socks_listener.is_none());
+        assert!(
+            reserved
+                .http_listener
+                .local_addr()
+                .unwrap()
+                .ip()
+                .is_loopback()
+        );
+        assert_ne!(
+            reserved.http_listener.local_addr().unwrap().port(),
+            busy_port
+        );
+    }
+
     #[test]
     fn proxy_url_env_value_resolves_lowercase_aliases() {
         let mut env = HashMap::new();
diff --git a/codex-rs/windows-sandbox-rs/sandbox_smoketests.py b/codex-rs/windows-sandbox-rs/sandbox_smoketests.py
index 0fc049d4e..f629a4c6d 100644
--- a/codex-rs/windows-sandbox-rs/sandbox_smoketests.py
+++ b/codex-rs/windows-sandbox-rs/sandbox_smoketests.py
@@ -6,8 +6,13 @@ import os
 import sys
 import shutil
 import subprocess
+import contextlib
+import http.client
+import http.server
+import threading
 from pathlib import Path
 from typing import List, Optional, Tuple
+from urllib.parse import urlsplit
 
 def _resolve_codex_cmd() -> List[str]:
     """Resolve the Codex CLI to invoke `codex sandbox windows`.
@@ -135,6 +140,68 @@ def make_symlink(link: Path, target: Path) -> bool:
     cp = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
     return cp.returncode == 0 and link.exists()
 
+class _QuietHandler(http.server.BaseHTTPRequestHandler):
+    def log_message(self, format, *args):
+        pass
+
+class _TargetHandler(_QuietHandler):
+    def do_GET(self):
+        body = b"proxy-ok"
+        self.send_response(200)
+        self.send_header("Content-Type", "text/plain")
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+class _ProxyHandler(_QuietHandler):
+    def do_GET(self):
+        parsed = urlsplit(self.path)
+        if not parsed.scheme or not parsed.hostname:
+            self.send_error(400, "absolute URL required")
+            return
+        if parsed.hostname not in ("127.0.0.1", "localhost"):
+            self.send_error(403, "only loopback hosts are allowed in smoke proxy")
+            return
+        path = parsed.path or "/"
+        if parsed.query:
+            path = f"{path}?{parsed.query}"
+        conn = None
+        try:
+            conn = http.client.HTTPConnection(parsed.hostname, parsed.port or 80, timeout=2)
+            conn.request("GET", path)
+            upstream = conn.getresponse()
+            body = upstream.read()
+        except Exception as err:
+            self.send_error(502, f"proxy upstream error: {err}")
+            return
+        finally:
+            if conn is not None:
+                with contextlib.suppress(Exception):
+                    conn.close()
+        self.send_response(upstream.status, upstream.reason)
+        self.send_header("Content-Type", "text/plain")
+        self.send_header("Content-Length", str(len(body)))
+        self.end_headers()
+        self.wfile.write(body)
+
+@contextlib.contextmanager
+def start_loopback_proxy_fixture():
+    target = http.server.ThreadingHTTPServer(("127.0.0.1", 0), _TargetHandler)
+    proxy = http.server.ThreadingHTTPServer(("127.0.0.1", 0), _ProxyHandler)
+    target_port = target.server_address[1]
+    proxy_port = proxy.server_address[1]
+    target_thread = threading.Thread(target=target.serve_forever, daemon=True)
+    proxy_thread = threading.Thread(target=proxy.serve_forever, daemon=True)
+    target_thread.start()
+    proxy_thread.start()
+    try:
+        yield target_port, proxy_port
+    finally:
+        proxy.shutdown()
+        target.shutdown()
+        proxy.server_close()
+        target.server_close()
+
 def summarize(results: List[CaseResult]) -> int:
     ok = sum(1 for r in results if r.ok)
     total = len(results)
@@ -278,7 +345,65 @@ def main() -> int:
                                "try { iwr http://neverssl.com -TimeoutSec 2 } catch { exit 1 }"], WS_ROOT)
     add("WS: iwr network blocked", rc != 0, f"rc={rc}")
 
-    # 17. RO: deny TEMP writes via PowerShell
+    # 17. WS: direct loopback blocked, proxy loopback allowed via env proxy
+    if have("curl"):
+        with start_loopback_proxy_fixture() as (target_port, proxy_port):
+            proxy_home = WS_ROOT / ".codex_proxy_smoke"
+            remove_if_exists(proxy_home)
+            proxy_home.mkdir(parents=True, exist_ok=True)
+            proxy_url = f"http://127.0.0.1:{proxy_port}"
+            proxy_env = {
+                "CODEX_HOME": str(proxy_home),
+                "HTTP_PROXY": proxy_url,
+                "http_proxy": proxy_url,
+                "ALL_PROXY": proxy_url,
+                "all_proxy": proxy_url,
+                "NO_PROXY": "",
+                "no_proxy": "",
+            }
+            proxied_cmd = [
+                "curl",
+                "--noproxy",
+                "",
+                "--connect-timeout",
+                "2",
+                "--max-time",
+                "4",
+                f"http://127.0.0.1:{target_port}/proxied",
+            ]
+            rc_proxy, out_proxy, err_proxy = run_sbx(
+                "workspace-write",
+                proxied_cmd,
+                WS_ROOT,
+                env_extra=proxy_env,
+            )
+            add(
+                "WS: loopback proxy allowed",
+                rc_proxy == 0 and "proxy-ok" in out_proxy,
+                f"rc={rc_proxy}, out={out_proxy}, err={err_proxy}",
+            )
+
+            direct_cmd = [
+                "curl",
+                "--noproxy",
+                "*",
+                "--connect-timeout",
+                "1",
+                "--max-time",
+                "2",
+                f"http://127.0.0.1:{target_port}/direct",
+            ]
+            rc_direct, _out_direct, err_direct = run_sbx(
+                "workspace-write",
+                direct_cmd,
+                WS_ROOT,
+                env_extra={"CODEX_HOME": str(proxy_home)},
+            )
+            add("WS: direct loopback blocked", rc_direct != 0, f"rc={rc_direct}, err={err_direct}")
+    else:
+        add("WS: direct/proxy loopback tests (curl missing)", True, "curl not installed")
+
+    # 18. RO: deny TEMP writes via PowerShell
     rc, out, err = run_sbx("read-only",
                            ["powershell", "-NoLogo", "-NoProfile", "-Command",
                             "Set-Content -LiteralPath $env:TEMP\\ro_tmpfail.txt -Value 'x'"], WS_ROOT)
@@ -287,21 +412,21 @@ def main() -> int:
     else:
         add("RO: TEMP write denied (PS, skipped)", True)
 
-    # 18. WS: curl version check — don't rely on stub, just succeed
+    # 19. WS: curl version check — don't rely on stub, just succeed
     if have("curl"):
         rc, out, err = run_sbx("workspace-write", ["cmd", "/c", "curl --version"], WS_ROOT)
         add("WS: curl present (version prints)", rc == 0, f"rc={rc}, err={err}")
     else:
         add("WS: curl present (optional, skipped)", True)
 
-    # 19. Optional: ripgrep version
+    # 20. Optional: ripgrep version
     if have("rg"):
         rc, out, err = run_sbx("workspace-write", ["cmd", "/c", "rg --version"], WS_ROOT)
         add("WS: rg --version (optional)", rc == 0, f"rc={rc}, err={err}")
     else:
         add("WS: rg --version (optional, skipped)", True)
 
-    # 20. Optional: git --version
+    # 21. Optional: git --version
     if have("git"):
         rc, out, err = run_sbx("workspace-write", ["git", "--version"], WS_ROOT)
         add("WS: git --version (optional)", rc == 0, f"rc={rc}, err={err}")
diff --git a/codex-rs/windows-sandbox-rs/src/elevated_impl.rs b/codex-rs/windows-sandbox-rs/src/elevated_impl.rs
index f6c4563e1..365ac37d6 100644
--- a/codex-rs/windows-sandbox-rs/src/elevated_impl.rs
+++ b/codex-rs/windows-sandbox-rs/src/elevated_impl.rs
@@ -1,4 +1,20 @@
+use std::collections::HashMap;
+use std::path::Path;
+
+pub struct ElevatedSandboxCaptureRequest<'a> {
+    pub policy_json_or_preset: &'a str,
+    pub sandbox_policy_cwd: &'a Path,
+    pub codex_home: &'a Path,
+    pub command: Vec<String>,
+    pub cwd: &'a Path,
+    pub env_map: HashMap<String, String>,
+    pub timeout_ms: Option<u64>,
+    pub use_private_desktop: bool,
+    pub proxy_enforced: bool,
+}
+
 mod windows_impl {
+    use super::ElevatedSandboxCaptureRequest;
     use crate::acl::allow_null_device;
     use crate::allow::compute_allow_paths;
     use crate::allow::AllowDenyPaths;
@@ -203,15 +219,19 @@ mod windows_impl {
     /// Launches the command runner under the sandbox user and captures its output.
     #[allow(clippy::too_many_arguments)]
     pub fn run_windows_sandbox_capture(
-        policy_json_or_preset: &str,
-        sandbox_policy_cwd: &Path,
-        codex_home: &Path,
-        command: Vec<String>,
-        cwd: &Path,
-        mut env_map: HashMap<String, String>,
-        timeout_ms: Option<u64>,
-        use_private_desktop: bool,
+        request: ElevatedSandboxCaptureRequest<'_>,
     ) -> Result<CaptureResult> {
+        let ElevatedSandboxCaptureRequest {
+            policy_json_or_preset,
+            sandbox_policy_cwd,
+            codex_home,
+            command,
+            cwd,
+            mut env_map,
+            timeout_ms,
+            use_private_desktop,
+            proxy_enforced,
+        } = request;
         let policy = parse_policy(policy_json_or_preset)?;
         normalize_null_device_env(&mut env_map);
         ensure_non_interactive_pager(&mut env_map);
@@ -224,8 +244,14 @@ mod windows_impl {
 
         let logs_base_dir: Option<&Path> = Some(sandbox_base.as_path());
         log_start(&command, logs_base_dir);
-        let sandbox_creds =
-            require_logon_sandbox_creds(&policy, sandbox_policy_cwd, cwd, &env_map, codex_home)?;
+        let sandbox_creds = require_logon_sandbox_creds(
+            &policy,
+            sandbox_policy_cwd,
+            cwd,
+            &env_map,
+            codex_home,
+            proxy_enforced,
+        )?;
         let sandbox_sid = resolve_sid(&sandbox_creds.username).map_err(|err: anyhow::Error| {
             io::Error::new(io::ErrorKind::PermissionDenied, err.to_string())
         })?;
@@ -480,11 +506,9 @@ pub use windows_impl::run_windows_sandbox_capture;
 
 #[cfg(not(target_os = "windows"))]
 mod stub {
+    use super::ElevatedSandboxCaptureRequest;
     use anyhow::bail;
     use anyhow::Result;
-    use codex_protocol::protocol::SandboxPolicy;
-    use std::collections::HashMap;
-    use std::path::Path;
 
     #[derive(Debug, Default)]
     pub struct CaptureResult {
@@ -497,14 +521,7 @@ mod stub {
     /// Stub implementation for non-Windows targets; sandboxing only works on Windows.
     #[allow(clippy::too_many_arguments)]
     pub fn run_windows_sandbox_capture(
-        _policy_json_or_preset: &str,
-        _sandbox_policy_cwd: &Path,
-        _codex_home: &Path,
-        _command: Vec<String>,
-        _cwd: &Path,
-        _env_map: HashMap<String, String>,
-        _timeout_ms: Option<u64>,
-        _use_private_desktop: bool,
+        _request: ElevatedSandboxCaptureRequest<'_>,
     ) -> Result<CaptureResult> {
         bail!("Windows sandbox is only available on Windows")
     }
diff --git a/codex-rs/windows-sandbox-rs/src/firewall.rs b/codex-rs/windows-sandbox-rs/src/firewall.rs
index b4939fd42..a95d3b57e 100644
--- a/codex-rs/windows-sandbox-rs/src/firewall.rs
+++ b/codex-rs/windows-sandbox-rs/src/firewall.rs
@@ -9,10 +9,13 @@ use windows::core::BSTR;
 use windows::Win32::Foundation::VARIANT_TRUE;
 use windows::Win32::NetworkManagement::WindowsFirewall::INetFwPolicy2;
 use windows::Win32::NetworkManagement::WindowsFirewall::INetFwRule3;
+use windows::Win32::NetworkManagement::WindowsFirewall::INetFwRules;
 use windows::Win32::NetworkManagement::WindowsFirewall::NetFwPolicy2;
 use windows::Win32::NetworkManagement::WindowsFirewall::NetFwRule;
 use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_ACTION_BLOCK;
 use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_IP_PROTOCOL_ANY;
+use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_IP_PROTOCOL_TCP;
+use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_IP_PROTOCOL_UDP;
 use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_PROFILE2_ALL;
 use windows::Win32::NetworkManagement::WindowsFirewall::NET_FW_RULE_DIR_OUT;
 use windows::Win32::System::Com::CoCreateInstance;
@@ -27,9 +30,128 @@ use codex_windows_sandbox::SetupFailure;
 // This is the stable identifier we use to find/update the rule idempotently.
 // It intentionally does not change between installs.
 const OFFLINE_BLOCK_RULE_NAME: &str = "codex_sandbox_offline_block_outbound";
+const OFFLINE_BLOCK_LOOPBACK_TCP_RULE_NAME: &str = "codex_sandbox_offline_block_loopback_tcp";
+const OFFLINE_BLOCK_LOOPBACK_UDP_RULE_NAME: &str = "codex_sandbox_offline_block_loopback_udp";
 
 // Friendly text shown in the firewall UI.
-const OFFLINE_BLOCK_RULE_FRIENDLY: &str = "Codex Sandbox Offline - Block Outbound";
+const OFFLINE_BLOCK_RULE_FRIENDLY: &str = "Codex Sandbox Offline - Block Non-Loopback Outbound";
+const OFFLINE_BLOCK_LOOPBACK_TCP_RULE_FRIENDLY: &str =
+    "Codex Sandbox Offline - Block Loopback TCP (Except Proxy)";
+const OFFLINE_BLOCK_LOOPBACK_UDP_RULE_FRIENDLY: &str = "Codex Sandbox Offline - Block Loopback UDP";
+const OFFLINE_PROXY_ALLOW_RULE_NAME: &str = "codex_sandbox_offline_allow_loopback_proxy";
+const LOOPBACK_REMOTE_ADDRESSES: &str = "127.0.0.0/8,::1";
+const NON_LOOPBACK_REMOTE_ADDRESSES: &str =
+    "0.0.0.0-126.255.255.255,128.0.0.0-255.255.255.255,::,::2-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff";
+
+struct BlockRuleSpec<'a> {
+    internal_name: &'a str,
+    friendly_desc: &'a str,
+    protocol: i32,
+    local_user_spec: &'a str,
+    offline_sid: &'a str,
+    remote_addresses: Option<&'a str>,
+    remote_ports: Option<&'a str>,
+}
+
+pub fn ensure_offline_proxy_allowlist(
+    offline_sid: &str,
+    proxy_ports: &[u16],
+    allow_local_binding: bool,
+    log: &mut File,
+) -> Result<()> {
+    let local_user_spec = format!("O:LSD:(A;;CC;;;{offline_sid})");
+
+    let hr = unsafe { CoInitializeEx(None, COINIT_APARTMENTTHREADED) };
+    if hr.is_err() {
+        return Err(anyhow::Error::new(SetupFailure::new(
+            SetupErrorCode::HelperFirewallComInitFailed,
+            format!("CoInitializeEx failed: {hr:?}"),
+        )));
+    }
+
+    let result = unsafe {
+        (|| -> Result<()> {
+            let policy: INetFwPolicy2 = CoCreateInstance(&NetFwPolicy2, None, CLSCTX_INPROC_SERVER)
+                .map_err(|err| {
+                    anyhow::Error::new(SetupFailure::new(
+                        SetupErrorCode::HelperFirewallPolicyAccessFailed,
+                        format!("CoCreateInstance NetFwPolicy2 failed: {err:?}"),
+                    ))
+                })?;
+            let rules = policy.Rules().map_err(|err| {
+                anyhow::Error::new(SetupFailure::new(
+                    SetupErrorCode::HelperFirewallPolicyAccessFailed,
+                    format!("INetFwPolicy2::Rules failed: {err:?}"),
+                ))
+            })?;
+
+            if allow_local_binding {
+                // Remove the legacy overlapping allow rule before returning to the local-binding
+                // mode so stale proxy exceptions do not linger.
+                remove_rule_if_present(&rules, OFFLINE_PROXY_ALLOW_RULE_NAME, log)?;
+                remove_rule_if_present(&rules, OFFLINE_BLOCK_LOOPBACK_UDP_RULE_NAME, log)?;
+                remove_rule_if_present(&rules, OFFLINE_BLOCK_LOOPBACK_TCP_RULE_NAME, log)?;
+                return Ok(());
+            }
+
+            ensure_block_rule(
+                &rules,
+                &BlockRuleSpec {
+                    internal_name: OFFLINE_BLOCK_LOOPBACK_UDP_RULE_NAME,
+                    friendly_desc: OFFLINE_BLOCK_LOOPBACK_UDP_RULE_FRIENDLY,
+                    protocol: NET_FW_IP_PROTOCOL_UDP.0,
+                    local_user_spec: &local_user_spec,
+                    offline_sid,
+                    remote_addresses: Some(LOOPBACK_REMOTE_ADDRESSES),
+                    remote_ports: None,
+                },
+                log,
+            )?;
+
+            // Install a broad TCP loopback block before narrowing it to the allowed proxy port
+            // complement. If the narrowing update fails, the sandbox remains fail-closed.
+            ensure_block_rule(
+                &rules,
+                &BlockRuleSpec {
+                    internal_name: OFFLINE_BLOCK_LOOPBACK_TCP_RULE_NAME,
+                    friendly_desc: OFFLINE_BLOCK_LOOPBACK_TCP_RULE_FRIENDLY,
+                    protocol: NET_FW_IP_PROTOCOL_TCP.0,
+                    local_user_spec: &local_user_spec,
+                    offline_sid,
+                    remote_addresses: Some(LOOPBACK_REMOTE_ADDRESSES),
+                    remote_ports: None,
+                },
+                log,
+            )?;
+
+            // Remove the legacy overlapping allow rule only after the explicit block rules are in
+            // place so transitions back to proxy-only mode do not fail open.
+            remove_rule_if_present(&rules, OFFLINE_PROXY_ALLOW_RULE_NAME, log)?;
+
+            if let Some(blocked_remote_ports) = blocked_loopback_tcp_remote_ports(proxy_ports) {
+                ensure_block_rule(
+                    &rules,
+                    &BlockRuleSpec {
+                        internal_name: OFFLINE_BLOCK_LOOPBACK_TCP_RULE_NAME,
+                        friendly_desc: OFFLINE_BLOCK_LOOPBACK_TCP_RULE_FRIENDLY,
+                        protocol: NET_FW_IP_PROTOCOL_TCP.0,
+                        local_user_spec: &local_user_spec,
+                        offline_sid,
+                        remote_addresses: Some(LOOPBACK_REMOTE_ADDRESSES),
+                        remote_ports: Some(&blocked_remote_ports),
+                    },
+                    log,
+                )?;
+            }
+            Ok(())
+        })()
+    };
+
+    unsafe {
+        CoUninitialize();
+    }
+    result
+}
 
 pub fn ensure_offline_outbound_block(offline_sid: &str, log: &mut File) -> Result<()> {
     let local_user_spec = format!("O:LSD:(A;;CC;;;{offline_sid})");
@@ -61,11 +183,15 @@ pub fn ensure_offline_outbound_block(offline_sid: &str, log: &mut File) -> Resul
             // Block all outbound IP protocols for this user.
             ensure_block_rule(
                 &rules,
-                OFFLINE_BLOCK_RULE_NAME,
-                OFFLINE_BLOCK_RULE_FRIENDLY,
-                NET_FW_IP_PROTOCOL_ANY.0,
-                &local_user_spec,
-                offline_sid,
+                &BlockRuleSpec {
+                    internal_name: OFFLINE_BLOCK_RULE_NAME,
+                    friendly_desc: OFFLINE_BLOCK_RULE_FRIENDLY,
+                    protocol: NET_FW_IP_PROTOCOL_ANY.0,
+                    local_user_spec: &local_user_spec,
+                    offline_sid,
+                    remote_addresses: Some(NON_LOOPBACK_REMOTE_ADDRESSES),
+                    remote_ports: None,
+                },
                 log,
             )?;
             Ok(())
@@ -78,16 +204,22 @@ pub fn ensure_offline_outbound_block(offline_sid: &str, log: &mut File) -> Resul
     result
 }
 
-fn ensure_block_rule(
-    rules: &windows::Win32::NetworkManagement::WindowsFirewall::INetFwRules,
-    internal_name: &str,
-    friendly_desc: &str,
-    protocol: i32,
-    local_user_spec: &str,
-    offline_sid: &str,
-    log: &mut File,
-) -> Result<()> {
+fn remove_rule_if_present(rules: &INetFwRules, internal_name: &str, log: &mut File) -> Result<()> {
     let name = BSTR::from(internal_name);
+    if unsafe { rules.Item(&name) }.is_ok() {
+        unsafe { rules.Remove(&name) }.map_err(|err| {
+            anyhow::Error::new(SetupFailure::new(
+                SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
+                format!("Rules::Remove failed for {internal_name}: {err:?}"),
+            ))
+        })?;
+        log_line(log, &format!("firewall rule removed name={internal_name}"))?;
+    }
+    Ok(())
+}
+
+fn ensure_block_rule(rules: &INetFwRules, spec: &BlockRuleSpec<'_>, log: &mut File) -> Result<()> {
+    let name = BSTR::from(spec.internal_name);
     let rule: INetFwRule3 = match unsafe { rules.Item(&name) } {
         Ok(existing) => existing.cast().map_err(|err| {
             anyhow::Error::new(SetupFailure::new(
@@ -112,13 +244,7 @@ fn ensure_block_rule(
                 ))
             })?;
             // Set all properties before adding the rule so we don't leave half-configured rules.
-            configure_rule(
-                &new_rule,
-                friendly_desc,
-                protocol,
-                local_user_spec,
-                offline_sid,
-            )?;
+            configure_rule(&new_rule, spec)?;
             unsafe { rules.Add(&new_rule) }.map_err(|err| {
                 anyhow::Error::new(SetupFailure::new(
                     SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
@@ -130,26 +256,24 @@ fn ensure_block_rule(
     };
 
     // Always re-apply fields to keep the setup idempotent.
-    configure_rule(&rule, friendly_desc, protocol, local_user_spec, offline_sid)?;
+    configure_rule(&rule, spec)?;
+
+    let remote_addresses_log = spec.remote_addresses.unwrap_or("*");
+    let remote_ports_log = spec.remote_ports.unwrap_or("*");
 
     log_line(
         log,
         &format!(
-            "firewall rule configured name={internal_name} protocol={protocol} LocalUserAuthorizedList={local_user_spec}"
+            "firewall rule configured name={} protocol={} RemoteAddresses={remote_addresses_log} RemotePorts={remote_ports_log} LocalUserAuthorizedList={}",
+            spec.internal_name, spec.protocol, spec.local_user_spec
         ),
     )?;
     Ok(())
 }
 
-fn configure_rule(
-    rule: &INetFwRule3,
-    friendly_desc: &str,
-    protocol: i32,
-    local_user_spec: &str,
-    offline_sid: &str,
-) -> Result<()> {
+fn configure_rule(rule: &INetFwRule3, spec: &BlockRuleSpec<'_>) -> Result<()> {
     unsafe {
-        rule.SetDescription(&BSTR::from(friendly_desc))
+        rule.SetDescription(&BSTR::from(spec.friendly_desc))
             .map_err(|err| {
                 anyhow::Error::new(SetupFailure::new(
                     SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
@@ -180,13 +304,29 @@ fn configure_rule(
                 format!("SetProfiles failed: {err:?}"),
             ))
         })?;
-        rule.SetProtocol(protocol).map_err(|err| {
+        rule.SetProtocol(spec.protocol).map_err(|err| {
             anyhow::Error::new(SetupFailure::new(
                 SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
                 format!("SetProtocol failed: {err:?}"),
             ))
         })?;
-        rule.SetLocalUserAuthorizedList(&BSTR::from(local_user_spec))
+        let remote_addresses = spec.remote_addresses.unwrap_or("*");
+        rule.SetRemoteAddresses(&BSTR::from(remote_addresses))
+            .map_err(|err| {
+                anyhow::Error::new(SetupFailure::new(
+                    SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
+                    format!("SetRemoteAddresses failed: {err:?}"),
+                ))
+            })?;
+        let remote_ports = spec.remote_ports.unwrap_or("*");
+        rule.SetRemotePorts(&BSTR::from(remote_ports))
+            .map_err(|err| {
+                anyhow::Error::new(SetupFailure::new(
+                    SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
+                    format!("SetRemotePorts failed: {err:?}"),
+                ))
+            })?;
+        rule.SetLocalUserAuthorizedList(&BSTR::from(spec.local_user_spec))
             .map_err(|err| {
                 anyhow::Error::new(SetupFailure::new(
                     SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
@@ -203,17 +343,59 @@ fn configure_rule(
         ))
     })?;
     let actual_str = actual.to_string();
-    if !actual_str.contains(offline_sid) {
+    if !actual_str.contains(spec.offline_sid) {
         return Err(anyhow::Error::new(SetupFailure::new(
             SetupErrorCode::HelperFirewallRuleVerifyFailed,
             format!(
-                "offline firewall rule user scope mismatch: expected SID {offline_sid}, got {actual_str}"
+                "offline firewall rule user scope mismatch: expected SID {}, got {actual_str}",
+                spec.offline_sid
             ),
         )));
     }
     Ok(())
 }
 
+fn blocked_loopback_tcp_remote_ports(proxy_ports: &[u16]) -> Option<String> {
+    let mut allowed_ports = proxy_ports
+        .iter()
+        .copied()
+        .filter(|port| *port != 0)
+        .collect::<Vec<_>>();
+    allowed_ports.sort_unstable();
+    allowed_ports.dedup();
+
+    let mut blocked_ranges = Vec::new();
+    let mut start = 1_u32;
+    for port in allowed_ports {
+        let port = u32::from(port);
+        if port < start {
+            continue;
+        }
+        if port > start {
+            blocked_ranges.push(port_range_string(start, port - 1));
+        }
+        start = port + 1;
+    }
+
+    if start <= u32::from(u16::MAX) {
+        blocked_ranges.push(port_range_string(start, u32::from(u16::MAX)));
+    }
+
+    if blocked_ranges.is_empty() {
+        None
+    } else {
+        Some(blocked_ranges.join(","))
+    }
+}
+
+fn port_range_string(start: u32, end: u32) -> String {
+    if start == end {
+        start.to_string()
+    } else {
+        format!("{start}-{end}")
+    }
+}
+
 fn log_line(log: &mut File, msg: &str) -> Result<()> {
     let ts = chrono::Utc::now().to_rfc3339();
     writeln!(log, "[{ts}] {msg}")?;
diff --git a/codex-rs/windows-sandbox-rs/src/identity.rs b/codex-rs/windows-sandbox-rs/src/identity.rs
index b9d5e29ed..b7768c1a3 100644
--- a/codex-rs/windows-sandbox-rs/src/identity.rs
+++ b/codex-rs/windows-sandbox-rs/src/identity.rs
@@ -3,9 +3,11 @@ use crate::logging::debug_log;
 use crate::policy::SandboxPolicy;
 use crate::setup::gather_read_roots;
 use crate::setup::gather_write_roots;
+use crate::setup::offline_proxy_settings_from_env;
 use crate::setup::run_elevated_setup;
 use crate::setup::sandbox_users_path;
 use crate::setup::setup_marker_path;
+use crate::setup::SandboxNetworkIdentity;
 use crate::setup::SandboxUserRecord;
 use crate::setup::SandboxUsersFile;
 use crate::setup::SetupMarker;
@@ -33,7 +35,8 @@ pub struct SandboxCreds {
 /// Returns true when the on-disk setup artifacts exist and match the current
 /// setup version.
 ///
-/// This reuses the same marker/users validation used by `require_logon_sandbox_creds`.
+/// This is a coarse readiness check; `require_logon_sandbox_creds` performs the
+/// additional runtime validation for offline firewall settings.
 pub fn sandbox_setup_is_complete(codex_home: &Path) -> bool {
     let marker_ok = matches!(load_marker(codex_home), Ok(Some(marker)) if marker.version_matches());
     if !marker_ok {
@@ -101,7 +104,10 @@ fn decode_password(record: &SandboxUserRecord) -> Result<String> {
     Ok(pwd)
 }
 
-fn select_identity(policy: &SandboxPolicy, codex_home: &Path) -> Result<Option<SandboxIdentity>> {
+fn select_identity(
+    network_identity: SandboxNetworkIdentity,
+    codex_home: &Path,
+) -> Result<Option<SandboxIdentity>> {
     let _marker = match load_marker(codex_home)? {
         Some(m) if m.version_matches() => m,
         _ => return Ok(None),
@@ -110,10 +116,9 @@ fn select_identity(policy: &SandboxPolicy, codex_home: &Path) -> Result<Option<S
         Some(u) if u.version_matches() => u,
         _ => return Ok(None),
     };
-    let chosen = if !policy.has_full_network_access() {
-        users.offline
-    } else {
-        users.online
+    let chosen = match network_identity {
+        SandboxNetworkIdentity::Offline => users.offline,
+        SandboxNetworkIdentity::Online => users.online,
     };
     let password = decode_password(&chosen)?;
     Ok(Some(SandboxIdentity {
@@ -128,25 +133,34 @@ pub fn require_logon_sandbox_creds(
     command_cwd: &Path,
     env_map: &HashMap<String, String>,
     codex_home: &Path,
+    proxy_enforced: bool,
 ) -> Result<SandboxCreds> {
     let sandbox_dir = crate::setup::sandbox_dir(codex_home);
     let needed_read = gather_read_roots(command_cwd, policy, codex_home);
     let needed_write = gather_write_roots(policy, policy_cwd, command_cwd, env_map);
+    let network_identity = SandboxNetworkIdentity::from_policy(policy, proxy_enforced);
+    let desired_offline_proxy_settings =
+        offline_proxy_settings_from_env(env_map, network_identity);
     // NOTE: Do not add CODEX_HOME/.sandbox to `needed_write`; it must remain non-writable by the
     // restricted capability token. The setup helper's `lock_sandbox_dir` is responsible for
     // granting the sandbox group access to this directory without granting the capability SID.
     let mut setup_reason: Option<String> = None;
-    let mut _existing_marker: Option<SetupMarker> = None;
 
     let mut identity = match load_marker(codex_home)? {
         Some(marker) if marker.version_matches() => {
-            _existing_marker = Some(marker.clone());
-            let selected = select_identity(policy, codex_home)?;
-            if selected.is_none() {
-                setup_reason =
-                    Some("sandbox users missing or incompatible with marker version".to_string());
+            if let Some(reason) =
+                marker.request_mismatch_reason(network_identity, &desired_offline_proxy_settings)
+            {
+                setup_reason = Some(reason);
+                None
+            } else {
+                let selected = select_identity(network_identity, codex_home)?;
+                if selected.is_none() {
+                    setup_reason =
+                        Some("sandbox users missing or incompatible with marker version".to_string());
+                }
+                selected
             }
-            selected
         }
         _ => {
             setup_reason = Some("sandbox setup marker missing or incompatible".to_string());
@@ -164,18 +178,30 @@ pub fn require_logon_sandbox_creds(
             crate::logging::log_note("sandbox setup required", Some(&sandbox_dir));
         }
         run_elevated_setup(
-            policy,
-            policy_cwd,
-            command_cwd,
-            env_map,
-            codex_home,
-            Some(needed_read.clone()),
-            Some(needed_write.clone()),
+            crate::setup::SandboxSetupRequest {
+                policy,
+                policy_cwd,
+                command_cwd,
+                env_map,
+                codex_home,
+                proxy_enforced,
+            },
+            crate::setup::SetupRootOverrides {
+                read_roots: Some(needed_read.clone()),
+                write_roots: Some(needed_write.clone()),
+            },
         )?;
-        identity = select_identity(policy, codex_home)?;
+        identity = select_identity(network_identity, codex_home)?;
     }
     // Always refresh ACLs (non-elevated) for current roots via the setup binary.
-    crate::setup::run_setup_refresh(policy, policy_cwd, command_cwd, env_map, codex_home)?;
+    crate::setup::run_setup_refresh(
+        policy,
+        policy_cwd,
+        command_cwd,
+        env_map,
+        codex_home,
+        proxy_enforced,
+    )?;
     let identity = identity.ok_or_else(|| {
         anyhow!(
             "Windows sandbox setup is missing or out of date; rerun the sandbox setup with elevation"
diff --git a/codex-rs/windows-sandbox-rs/src/lib.rs b/codex-rs/windows-sandbox-rs/src/lib.rs
index 73193a207..11afda750 100644
--- a/codex-rs/windows-sandbox-rs/src/lib.rs
+++ b/codex-rs/windows-sandbox-rs/src/lib.rs
@@ -72,6 +72,8 @@ pub use dpapi::unprotect as dpapi_unprotect;
 #[cfg(target_os = "windows")]
 pub use elevated_impl::run_windows_sandbox_capture as run_windows_sandbox_capture_elevated;
 #[cfg(target_os = "windows")]
+pub use elevated_impl::ElevatedSandboxCaptureRequest;
+#[cfg(target_os = "windows")]
 pub use helper_materialization::resolve_current_exe_for_launch;
 #[cfg(target_os = "windows")]
 pub use hide_users::hide_current_user_profile_dir;
@@ -116,6 +118,10 @@ pub use setup::sandbox_dir;
 #[cfg(target_os = "windows")]
 pub use setup::sandbox_secrets_dir;
 #[cfg(target_os = "windows")]
+pub use setup::SandboxSetupRequest;
+#[cfg(target_os = "windows")]
+pub use setup::SetupRootOverrides;
+#[cfg(target_os = "windows")]
 pub use setup::SETUP_VERSION;
 #[cfg(target_os = "windows")]
 pub use setup_error::extract_failure as extract_setup_failure;
diff --git a/codex-rs/windows-sandbox-rs/src/sandbox_users.rs b/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
index 5ab39c3ce..e006b696f 100644
--- a/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
+++ b/codex-rs/windows-sandbox-rs/src/sandbox_users.rs
@@ -63,6 +63,8 @@ pub fn provision_sandbox_users(
     codex_home: &Path,
     offline_username: &str,
     online_username: &str,
+    proxy_ports: &[u16],
+    allow_local_binding: bool,
     log: &mut File,
 ) -> Result<()> {
     ensure_sandbox_users_group(log)?;
@@ -80,6 +82,8 @@ pub fn provision_sandbox_users(
         &offline_password,
         online_username,
         &online_password,
+        proxy_ports,
+        allow_local_binding,
     )?;
     Ok(())
 }
@@ -388,6 +392,8 @@ struct SetupMarker {
     offline_username: String,
     online_username: String,
     created_at: String,
+    proxy_ports: Vec<u16>,
+    allow_local_binding: bool,
     read_roots: Vec<PathBuf>,
     write_roots: Vec<PathBuf>,
 }
@@ -398,6 +404,8 @@ fn write_secrets(
     offline_pwd: &str,
     online_user: &str,
     online_pwd: &str,
+    proxy_ports: &[u16],
+    allow_local_binding: bool,
 ) -> Result<()> {
     let sandbox_dir = sandbox_dir(codex_home);
     std::fs::create_dir_all(&sandbox_dir).map_err(|err| {
@@ -447,6 +455,8 @@ fn write_secrets(
         offline_username: offline_user.to_string(),
         online_username: online_user.to_string(),
         created_at: chrono::Utc::now().to_rfc3339(),
+        proxy_ports: proxy_ports.to_vec(),
+        allow_local_binding,
         read_roots: Vec::new(),
         write_roots: Vec::new(),
     };
diff --git a/codex-rs/windows-sandbox-rs/src/setup_main_win.rs b/codex-rs/windows-sandbox-rs/src/setup_main_win.rs
index 86c1d104e..8a72b22a9 100644
--- a/codex-rs/windows-sandbox-rs/src/setup_main_win.rs
+++ b/codex-rs/windows-sandbox-rs/src/setup_main_win.rs
@@ -84,6 +84,10 @@ struct Payload {
     command_cwd: PathBuf,
     read_roots: Vec<PathBuf>,
     write_roots: Vec<PathBuf>,
+    #[serde(default)]
+    proxy_ports: Vec<u16>,
+    #[serde(default)]
+    allow_local_binding: bool,
     real_user: String,
     #[serde(default)]
     mode: SetupMode,
@@ -510,6 +514,8 @@ fn run_setup_full(payload: &Payload, log: &mut File, sbx_dir: &Path) -> Result<(
             &payload.codex_home,
             &payload.offline_username,
             &payload.online_username,
+            &payload.proxy_ports,
+            payload.allow_local_binding,
             log,
         );
         if let Err(err) = provision_result {
@@ -572,6 +578,21 @@ fn run_setup_full(payload: &Payload, log: &mut File, sbx_dir: &Path) -> Result<(
     };
     let mut refresh_errors: Vec<String> = Vec::new();
     if !refresh_only {
+        let proxy_allowlist_result = firewall::ensure_offline_proxy_allowlist(
+            &offline_sid_str,
+            &payload.proxy_ports,
+            payload.allow_local_binding,
+            log,
+        );
+        if let Err(err) = proxy_allowlist_result {
+            if extract_setup_failure(&err).is_some() {
+                return Err(err);
+            }
+            return Err(anyhow::Error::new(SetupFailure::new(
+                SetupErrorCode::HelperFirewallRuleCreateOrAddFailed,
+                format!("ensure offline proxy allowlist failed: {err}"),
+            )));
+        }
         let firewall_result = firewall::ensure_offline_outbound_block(&offline_sid_str, log);
         if let Err(err) = firewall_result {
             if extract_setup_failure(&err).is_some() {
diff --git a/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs b/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs
index 3296d09c4..962a53d60 100644
--- a/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs
+++ b/codex-rs/windows-sandbox-rs/src/setup_orchestrator.rs
@@ -1,5 +1,6 @@
 use serde::Deserialize;
 use serde::Serialize;
+use std::collections::BTreeSet;
 use std::collections::HashMap;
 use std::collections::HashSet;
 use std::ffi::c_void;
@@ -78,21 +79,39 @@ pub fn sandbox_users_path(codex_home: &Path) -> PathBuf {
     sandbox_secrets_dir(codex_home).join("sandbox_users.json")
 }
 
+pub struct SandboxSetupRequest<'a> {
+    pub policy: &'a SandboxPolicy,
+    pub policy_cwd: &'a Path,
+    pub command_cwd: &'a Path,
+    pub env_map: &'a HashMap<String, String>,
+    pub codex_home: &'a Path,
+    pub proxy_enforced: bool,
+}
+
+#[derive(Default)]
+pub struct SetupRootOverrides {
+    pub read_roots: Option<Vec<PathBuf>>,
+    pub write_roots: Option<Vec<PathBuf>>,
+}
+
 pub fn run_setup_refresh(
     policy: &SandboxPolicy,
     policy_cwd: &Path,
     command_cwd: &Path,
     env_map: &HashMap<String, String>,
     codex_home: &Path,
+    proxy_enforced: bool,
 ) -> Result<()> {
     run_setup_refresh_inner(
-        policy,
-        policy_cwd,
-        command_cwd,
-        env_map,
-        codex_home,
-        /*read_roots_override*/ None,
-        /*write_roots_override*/ None,
+        SandboxSetupRequest {
+            policy,
+            policy_cwd,
+            command_cwd,
+            env_map,
+            codex_home,
+            proxy_enforced,
+        },
+        SetupRootOverrides::default(),
     )
 }
 
@@ -103,53 +122,51 @@ pub fn run_setup_refresh_with_extra_read_roots(
     env_map: &HashMap<String, String>,
     codex_home: &Path,
     extra_read_roots: Vec<PathBuf>,
+    proxy_enforced: bool,
 ) -> Result<()> {
     let mut read_roots = gather_read_roots(command_cwd, policy, codex_home);
     read_roots.extend(extra_read_roots);
     run_setup_refresh_inner(
-        policy,
-        policy_cwd,
-        command_cwd,
-        env_map,
-        codex_home,
-        Some(read_roots),
-        Some(Vec::new()),
+        SandboxSetupRequest {
+            policy,
+            policy_cwd,
+            command_cwd,
+            env_map,
+            codex_home,
+            proxy_enforced,
+        },
+        SetupRootOverrides {
+            read_roots: Some(read_roots),
+            write_roots: Some(Vec::new()),
+        },
     )
 }
 
 fn run_setup_refresh_inner(
-    policy: &SandboxPolicy,
-    policy_cwd: &Path,
-    command_cwd: &Path,
-    env_map: &HashMap<String, String>,
-    codex_home: &Path,
-    read_roots_override: Option<Vec<PathBuf>>,
-    write_roots_override: Option<Vec<PathBuf>>,
+    request: SandboxSetupRequest<'_>,
+    overrides: SetupRootOverrides,
 ) -> Result<()> {
     // Skip in danger-full-access.
     if matches!(
-        policy,
+        request.policy,
         SandboxPolicy::DangerFullAccess | SandboxPolicy::ExternalSandbox { .. }
     ) {
         return Ok(());
     }
-    let (read_roots, write_roots) = build_payload_roots(
-        policy,
-        policy_cwd,
-        command_cwd,
-        env_map,
-        codex_home,
-        read_roots_override,
-        write_roots_override,
-    );
+    let (read_roots, write_roots) = build_payload_roots(&request, overrides);
+    let network_identity =
+        SandboxNetworkIdentity::from_policy(request.policy, request.proxy_enforced);
+    let offline_proxy_settings = offline_proxy_settings_from_env(request.env_map, network_identity);
     let payload = ElevationPayload {
         version: SETUP_VERSION,
         offline_username: OFFLINE_USERNAME.to_string(),
         online_username: ONLINE_USERNAME.to_string(),
-        codex_home: codex_home.to_path_buf(),
-        command_cwd: command_cwd.to_path_buf(),
+        codex_home: request.codex_home.to_path_buf(),
+        command_cwd: request.command_cwd.to_path_buf(),
         read_roots,
         write_roots,
+        proxy_ports: offline_proxy_settings.proxy_ports,
+        allow_local_binding: offline_proxy_settings.allow_local_binding,
         real_user: std::env::var("USERNAME").unwrap_or_else(|_| "Administrators".to_string()),
         refresh_only: true,
     };
@@ -159,7 +176,7 @@ fn run_setup_refresh_inner(
     // Refresh should never request elevation; ensure verb isn't set and we don't trigger UAC.
     let mut cmd = Command::new(&exe);
     cmd.arg(&b64).stdout(Stdio::null()).stderr(Stdio::null());
-    let cwd = std::env::current_dir().unwrap_or_else(|_| codex_home.to_path_buf());
+    let cwd = std::env::current_dir().unwrap_or_else(|_| request.codex_home.to_path_buf());
     log_note(
         &format!(
             "setup refresh: spawning {} (cwd={}, payload_len={})",
@@ -167,14 +184,14 @@ fn run_setup_refresh_inner(
             cwd.display(),
             b64.len()
         ),
-        Some(&sandbox_dir(codex_home)),
+        Some(&sandbox_dir(request.codex_home)),
     );
     let status = cmd
         .status()
         .map_err(|e| {
             log_note(
                 &format!("setup refresh: failed to spawn {}: {e}", exe.display()),
-                Some(&sandbox_dir(codex_home)),
+                Some(&sandbox_dir(request.codex_home)),
             );
             e
         })
@@ -182,7 +199,7 @@ fn run_setup_refresh_inner(
     if !status.success() {
         log_note(
             &format!("setup refresh: exited with status {status:?}"),
-            Some(&sandbox_dir(codex_home)),
+            Some(&sandbox_dir(request.codex_home)),
         );
         return Err(anyhow!("setup refresh failed with status {}", status));
     }
@@ -196,12 +213,38 @@ pub struct SetupMarker {
     pub online_username: String,
     #[serde(default)]
     pub created_at: Option<String>,
+    #[serde(default)]
+    pub proxy_ports: Vec<u16>,
+    #[serde(default)]
+    pub allow_local_binding: bool,
 }
 
 impl SetupMarker {
     pub fn version_matches(&self) -> bool {
         self.version == SETUP_VERSION
     }
+
+    pub(crate) fn request_mismatch_reason(
+        &self,
+        network_identity: SandboxNetworkIdentity,
+        offline_proxy_settings: &OfflineProxySettings,
+    ) -> Option<String> {
+        if !network_identity.uses_offline_identity() {
+            return None;
+        }
+        if self.proxy_ports == offline_proxy_settings.proxy_ports
+            && self.allow_local_binding == offline_proxy_settings.allow_local_binding
+        {
+            return None;
+        }
+        Some(format!(
+            "offline firewall settings changed (stored_ports={:?}, desired_ports={:?}, stored_allow_local_binding={}, desired_allow_local_binding={})",
+            self.proxy_ports,
+            offline_proxy_settings.proxy_ports,
+            self.allow_local_binding,
+            offline_proxy_settings.allow_local_binding
+        ))
+    }
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
@@ -390,11 +433,106 @@ struct ElevationPayload {
     command_cwd: PathBuf,
     read_roots: Vec<PathBuf>,
     write_roots: Vec<PathBuf>,
+    #[serde(default)]
+    proxy_ports: Vec<u16>,
+    #[serde(default)]
+    allow_local_binding: bool,
     real_user: String,
     #[serde(default)]
     refresh_only: bool,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct OfflineProxySettings {
+    pub proxy_ports: Vec<u16>,
+    pub allow_local_binding: bool,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum SandboxNetworkIdentity {
+    Offline,
+    Online,
+}
+
+impl SandboxNetworkIdentity {
+    pub(crate) fn from_policy(policy: &SandboxPolicy, proxy_enforced: bool) -> Self {
+        if proxy_enforced || !policy.has_full_network_access() {
+            Self::Offline
+        } else {
+            Self::Online
+        }
+    }
+
+    pub(crate) fn uses_offline_identity(self) -> bool {
+        matches!(self, Self::Offline)
+    }
+}
+
+const PROXY_ENV_KEYS: &[&str] = &[
+    "HTTP_PROXY",
+    "HTTPS_PROXY",
+    "ALL_PROXY",
+    "WS_PROXY",
+    "WSS_PROXY",
+    "http_proxy",
+    "https_proxy",
+    "all_proxy",
+    "ws_proxy",
+    "wss_proxy",
+];
+const ALLOW_LOCAL_BINDING_ENV_KEY: &str = "CODEX_NETWORK_ALLOW_LOCAL_BINDING";
+
+pub(crate) fn offline_proxy_settings_from_env(
+    env_map: &HashMap<String, String>,
+    network_identity: SandboxNetworkIdentity,
+) -> OfflineProxySettings {
+    if !network_identity.uses_offline_identity() {
+        return OfflineProxySettings {
+            proxy_ports: vec![],
+            allow_local_binding: false,
+        };
+    }
+    OfflineProxySettings {
+        proxy_ports: proxy_ports_from_env(env_map),
+        allow_local_binding: env_map
+            .get(ALLOW_LOCAL_BINDING_ENV_KEY)
+            .is_some_and(|value| value == "1"),
+    }
+}
+
+pub(crate) fn proxy_ports_from_env(env_map: &HashMap<String, String>) -> Vec<u16> {
+    let mut ports = BTreeSet::new();
+    for key in PROXY_ENV_KEYS {
+        if let Some(value) = env_map.get(*key) {
+            if let Some(port) = loopback_proxy_port_from_url(value) {
+                ports.insert(port);
+            }
+        }
+    }
+    ports.into_iter().collect()
+}
+
+fn loopback_proxy_port_from_url(url: &str) -> Option<u16> {
+    let authority = url.trim().split_once("://")?.1.split('/').next()?;
+    let host_port = authority.rsplit_once('@').map_or(authority, |(_, hp)| hp);
+
+    if let Some(host) = host_port.strip_prefix('[') {
+        let (host, rest) = host.split_once(']')?;
+        if host != "::1" {
+            return None;
+        }
+        let port = rest.strip_prefix(':')?.parse::<u16>().ok()?;
+        return (port != 0).then_some(port);
+    }
+
+    let (host, port) = host_port.rsplit_once(':')?;
+    if !(host.eq_ignore_ascii_case("localhost") || host == "127.0.0.1") {
+        return None;
+    }
+    let port = port.parse::<u16>().ok()?;
+    (port != 0).then_some(port)
+}
+
 fn quote_arg(arg: &str) -> String {
     let needs = arg.is_empty()
         || arg
@@ -574,39 +712,31 @@ fn run_setup_exe(
 }
 
 pub fn run_elevated_setup(
-    policy: &SandboxPolicy,
-    policy_cwd: &Path,
-    command_cwd: &Path,
-    env_map: &HashMap<String, String>,
-    codex_home: &Path,
-    read_roots_override: Option<Vec<PathBuf>>,
-    write_roots_override: Option<Vec<PathBuf>>,
+    request: SandboxSetupRequest<'_>,
+    overrides: SetupRootOverrides,
 ) -> Result<()> {
     // Ensure the shared sandbox directory exists before we send it to the elevated helper.
-    let sbx_dir = sandbox_dir(codex_home);
+    let sbx_dir = sandbox_dir(request.codex_home);
     std::fs::create_dir_all(&sbx_dir).map_err(|err| {
         failure(
             SetupErrorCode::OrchestratorSandboxDirCreateFailed,
             format!("failed to create sandbox dir {}: {err}", sbx_dir.display()),
         )
     })?;
-    let (read_roots, write_roots) = build_payload_roots(
-        policy,
-        policy_cwd,
-        command_cwd,
-        env_map,
-        codex_home,
-        read_roots_override,
-        write_roots_override,
-    );
+    let (read_roots, write_roots) = build_payload_roots(&request, overrides);
+    let network_identity =
+        SandboxNetworkIdentity::from_policy(request.policy, request.proxy_enforced);
+    let offline_proxy_settings = offline_proxy_settings_from_env(request.env_map, network_identity);
     let payload = ElevationPayload {
         version: SETUP_VERSION,
         offline_username: OFFLINE_USERNAME.to_string(),
         online_username: ONLINE_USERNAME.to_string(),
-        codex_home: codex_home.to_path_buf(),
-        command_cwd: command_cwd.to_path_buf(),
+        codex_home: request.codex_home.to_path_buf(),
+        command_cwd: request.command_cwd.to_path_buf(),
         read_roots,
         write_roots,
+        proxy_ports: offline_proxy_settings.proxy_ports,
+        allow_local_binding: offline_proxy_settings.allow_local_binding,
         real_user: std::env::var("USERNAME").unwrap_or_else(|_| "Administrators".to_string()),
         refresh_only: false,
     };
@@ -616,28 +746,28 @@ pub fn run_elevated_setup(
             format!("failed to determine elevation state: {err}"),
         )
     })?;
-    run_setup_exe(&payload, needs_elevation, codex_home)
+    run_setup_exe(&payload, needs_elevation, request.codex_home)
 }
 
 fn build_payload_roots(
-    policy: &SandboxPolicy,
-    policy_cwd: &Path,
-    command_cwd: &Path,
-    env_map: &HashMap<String, String>,
-    codex_home: &Path,
-    read_roots_override: Option<Vec<PathBuf>>,
-    write_roots_override: Option<Vec<PathBuf>>,
+    request: &SandboxSetupRequest<'_>,
+    overrides: SetupRootOverrides,
 ) -> (Vec<PathBuf>, Vec<PathBuf>) {
-    let write_roots = if let Some(roots) = write_roots_override {
+    let write_roots = if let Some(roots) = overrides.write_roots {
         canonical_existing(&roots)
     } else {
-        gather_write_roots(policy, policy_cwd, command_cwd, env_map)
+        gather_write_roots(
+            request.policy,
+            request.policy_cwd,
+            request.command_cwd,
+            request.env_map,
+        )
     };
-    let write_roots = filter_sensitive_write_roots(write_roots, codex_home);
-    let mut read_roots = if let Some(roots) = read_roots_override {
+    let write_roots = filter_sensitive_write_roots(write_roots, request.codex_home);
+    let mut read_roots = if let Some(roots) = overrides.read_roots {
         canonical_existing(&roots)
     } else {
-        gather_read_roots(command_cwd, policy, codex_home)
+        gather_read_roots(request.command_cwd, request.policy, request.codex_home)
     };
     let write_root_set: HashSet<PathBuf> = write_roots.iter().cloned().collect();
     read_roots.retain(|root| !write_root_set.contains(root));
@@ -673,13 +803,17 @@ fn filter_sensitive_write_roots(mut roots: Vec<PathBuf>, codex_home: &Path) -> V
 mod tests {
     use super::gather_legacy_full_read_roots;
     use super::gather_read_roots;
+    use super::loopback_proxy_port_from_url;
+    use super::offline_proxy_settings_from_env;
     use super::profile_read_roots;
+    use super::proxy_ports_from_env;
     use super::WINDOWS_PLATFORM_DEFAULT_READ_ROOTS;
     use crate::helper_materialization::helper_bin_dir;
     use crate::policy::SandboxPolicy;
     use codex_protocol::protocol::ReadOnlyAccess;
     use codex_utils_absolute_path::AbsolutePathBuf;
     use pretty_assertions::assert_eq;
+    use std::collections::HashMap;
     use std::collections::HashSet;
     use std::fs;
     use std::path::PathBuf;
@@ -692,6 +826,143 @@ mod tests {
             .collect()
     }
 
+    #[test]
+    fn loopback_proxy_url_parsing_supports_common_forms() {
+        assert_eq!(
+            loopback_proxy_port_from_url("http://localhost:3128"),
+            Some(3128)
+        );
+        assert_eq!(
+            loopback_proxy_port_from_url("https://127.0.0.1:8080"),
+            Some(8080)
+        );
+        assert_eq!(
+            loopback_proxy_port_from_url("socks5h://user:pass@[::1]:1080"),
+            Some(1080)
+        );
+    }
+
+    #[test]
+    fn loopback_proxy_url_parsing_rejects_non_loopback_and_zero_port() {
+        assert_eq!(
+            loopback_proxy_port_from_url("http://example.com:3128"),
+            None
+        );
+        assert_eq!(loopback_proxy_port_from_url("http://127.0.0.1:0"), None);
+        assert_eq!(loopback_proxy_port_from_url("localhost:8080"), None);
+    }
+
+    #[test]
+    fn proxy_ports_from_env_dedupes_and_sorts() {
+        let mut env = HashMap::new();
+        env.insert(
+            "HTTP_PROXY".to_string(),
+            "http://127.0.0.1:8080".to_string(),
+        );
+        env.insert(
+            "http_proxy".to_string(),
+            "http://localhost:8080".to_string(),
+        );
+        env.insert("ALL_PROXY".to_string(), "socks5h://[::1]:1081".to_string());
+        env.insert(
+            "HTTPS_PROXY".to_string(),
+            "https://example.com:9999".to_string(),
+        );
+
+        assert_eq!(proxy_ports_from_env(&env), vec![1081, 8080]);
+    }
+
+    #[test]
+    fn offline_proxy_settings_ignore_proxy_env_when_online_identity_selected() {
+        let mut env = HashMap::new();
+        env.insert(
+            "HTTP_PROXY".to_string(),
+            "http://127.0.0.1:8080".to_string(),
+        );
+        env.insert(
+            "CODEX_NETWORK_ALLOW_LOCAL_BINDING".to_string(),
+            "1".to_string(),
+        );
+
+        assert_eq!(
+            offline_proxy_settings_from_env(&env, super::SandboxNetworkIdentity::Online),
+            super::OfflineProxySettings {
+                proxy_ports: vec![],
+                allow_local_binding: false,
+            }
+        );
+    }
+
+    #[test]
+    fn offline_proxy_settings_capture_proxy_ports_and_local_binding_for_offline_identity() {
+        let mut env = HashMap::new();
+        env.insert(
+            "HTTP_PROXY".to_string(),
+            "http://127.0.0.1:8080".to_string(),
+        );
+        env.insert(
+            "ALL_PROXY".to_string(),
+            "socks5h://127.0.0.1:1081".to_string(),
+        );
+        env.insert(
+            "CODEX_NETWORK_ALLOW_LOCAL_BINDING".to_string(),
+            "1".to_string(),
+        );
+
+        assert_eq!(
+            offline_proxy_settings_from_env(&env, super::SandboxNetworkIdentity::Offline),
+            super::OfflineProxySettings {
+                proxy_ports: vec![1081, 8080],
+                allow_local_binding: true,
+            }
+        );
+    }
+
+    #[test]
+    fn setup_marker_request_mismatch_reason_ignores_proxy_drift_for_online_identity() {
+        let marker = super::SetupMarker {
+            version: super::SETUP_VERSION,
+            offline_username: "offline".to_string(),
+            online_username: "online".to_string(),
+            created_at: None,
+            proxy_ports: vec![3128],
+            allow_local_binding: false,
+        };
+        let desired = super::OfflineProxySettings {
+            proxy_ports: vec![1081, 8080],
+            allow_local_binding: true,
+        };
+
+        assert_eq!(
+            marker.request_mismatch_reason(super::SandboxNetworkIdentity::Online, &desired),
+            None
+        );
+    }
+
+    #[test]
+    fn setup_marker_request_mismatch_reason_reports_offline_firewall_drift() {
+        let marker = super::SetupMarker {
+            version: super::SETUP_VERSION,
+            offline_username: "offline".to_string(),
+            online_username: "online".to_string(),
+            created_at: None,
+            proxy_ports: vec![3128],
+            allow_local_binding: false,
+        };
+        let desired = super::OfflineProxySettings {
+            proxy_ports: vec![1081, 8080],
+            allow_local_binding: true,
+        };
+
+        assert_eq!(
+            marker.request_mismatch_reason(super::SandboxNetworkIdentity::Offline, &desired),
+            Some(
+                "offline firewall settings changed (stored_ports=[3128], desired_ports=[1081, 8080], stored_allow_local_binding=false, desired_allow_local_binding=true)"
+                    .to_string()
+            )
+        );
+    }
+
     #[test]
     fn profile_read_roots_excludes_configured_top_level_entries() {
         let tmp = TempDir::new().expect("tempdir");