mitmproxy · keshavkrishna · Oct 12, 2025 · Oct 12, 2025 · Oct 12, 2025 · Oct 18, 2025
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,9 @@
 
 ## Unreleased: mitmproxy next
 
+- Make TCP inactivity timeout configurable through a new `tcp_timeout` option (default: 600 seconds).
+  Previously, the timeout was hardcoded to 10 minutes for all TCP connections.
+  ([#7909](https://github.com/mitmproxy/mitmproxy/pull/7909), @keshavkrishnadav)
 
 ## 15 October 2025: mitmproxy 12.2.0
 

diff --git a/mitmproxy/options.py b/mitmproxy/options.py
@@ -237,5 +237,13 @@ def __init__(self, **kwargs) -> None:
             None,
             "Path to a .proto file that's used to resolve Protobuf field names when pretty-printing.",
         )
+        self.add_option(
+            "tcp_timeout",
+            int,
+            600,
+            """
+            Timeout in seconds for inactive TCP connections. Connections will be closed after this period of inactivity.
+            """,
+        )
 
         self.update(**kwargs)
diff --git a/mitmproxy/proxy/server.py b/mitmproxy/proxy/server.py
@@ -44,7 +44,6 @@
 
 logger = logging.getLogger(__name__)
 
-TCP_TIMEOUT = 60 * 10
 UDP_TIMEOUT = 20
 
 
@@ -115,7 +114,7 @@ def __init__(self, context: Context) -> None:
         # on protocols that start with a server greeting.
         self.layer = layer.NextLayer(context, ask_on_start=True)
         if self.client.transport_protocol == "tcp":
-            timeout = TCP_TIMEOUT
+            timeout = context.options.tcp_timeout
         else:
             timeout = UDP_TIMEOUT
         self.timeout_watchdog = TimeoutWatchdog(timeout, self.on_timeout)

diff --git a/mitmproxy/tools/cmdline.py b/mitmproxy/tools/cmdline.py
@@ -105,6 +105,9 @@ def common_options(parser, opts):
     group = parser.add_argument_group("Modify Headers")
     opts.make_parser(group, "modify_headers", metavar="PATTERN", short="H")
 
+    # TCP Options
+    opts.make_parser(group, "tcp_timeout", metavar="SECONDS")
+
 
 def mitmproxy(opts):
     parser = argparse.ArgumentParser(usage="%(prog)s [options]")

diff --git a/test/mitmproxy/test_options.py b/test/mitmproxy/test_options.py
@@ -3,3 +3,13 @@
 
 def test_simple():
     assert options.Options()
+
+
+def test_tcp_timeout_default():
+    opts = options.Options()
+    assert opts.tcp_timeout == 600
+
+
+def test_tcp_timeout_settable():
+    opts = options.Options(tcp_timeout=123)
+    assert opts.tcp_timeout == 123
diff --git a/web/gen/options_js.py b/web/gen/options_js.py
@@ -17,17 +17,17 @@
 
 
 def _ts_type(t):
-    if t is bool:
+    if t == bool:  # noqa: E721
         return "boolean"
-    if t is str:
+    if t == str:  # noqa: E721
         return "string"
-    if t is int:
+    if t == int:  # noqa: E721
         return "number"
-    if t == Sequence[str]:
+    if t == Sequence[str]:  # noqa: E721
         return "string[]"
-    if t == str | None:
+    if t == str | None:  # noqa: E721
         return "string | undefined"
-    if t == int | None:
+    if t == int | None:  # noqa: E721
         return "number | undefined"
     raise RuntimeError(t)
 

diff --git a/web/src/js/ducks/_options_gen.ts b/web/src/js/ducks/_options_gen.ts
@@ -79,6 +79,7 @@ export interface OptionsState {
     stream_large_bodies: string | undefined;
     strip_ech: boolean;
     tcp_hosts: string[];
+    tcp_timeout: number;
     termlog_verbosity: string;
     tls_ecdh_curve_client: string | undefined;
     tls_ecdh_curve_server: string | undefined;
@@ -185,6 +186,7 @@ export const defaultState: OptionsState = {
     stream_large_bodies: undefined,
     strip_ech: true,
     tcp_hosts: [],
+    tcp_timeout: 600,
     termlog_verbosity: "info",
     tls_ecdh_curve_client: undefined,
     tls_ecdh_curve_server: undefined,