HttpWebRequest timeout not working

Question

HttpWebRequest timeout not working

Boyd Mills 0

The following code:

                    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(sRequest); // Create(sQuery);
                    request.Credentials = CredentialCache.DefaultCredentials;
                    request.Timeout = 10000;
                    request.ReadWriteTimeout = 10000;


                    // Get the response.
                    Console.WriteLine("Away we go "+ sRequest );
                    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                    Console.WriteLine("We are back");

hangs on the request.GetResponse(); When I disconnect the server. It never returns. It should return.
Running on Windows 10 using Visual Studio 2013

Please advise

Tom Surace 0 Reputation points

2026-07-01T22:44:58.86+00:00
I have been seeing the same problem for ages. If the server just stalls, you will trigger the Request timeouts. But if the server is killed, or the connection is dropped by a firewall that rudely in a way that does not send a FIN packet to close the socket (more common than you think), request.GetResponse() will hang forever, when GetResultStream internally calls InternalGetRequestStream().Result (async), which calls Task.GetResultCore() which calls InternalWait with an infinte timeout. And, voila, you have an infinite hang. Before the .NET Core split this code had the same problem, so it seems likely the old school async code was just ported to new async syntax without fixing the timeouts.

My reading suggests that most OSs will time out the TCP socket at ~2 hours on a typical network stack with default timeouts. So... it might as well hang forever. Since GetResponse is stalled on retrieving the socket status and has no timeout, and the server never sends a FIN, the network stack thinks both servers are alive and must wait for one or the other to terminate the socket before it can clean up.

Just you know .. it's real. You'll really only notice if you're behind a rude corporate firewall. And before you point out that "they really should fix the firewall", yes, I know. If you are a VIP who can dictate IP filtering policy over all of our customer's IT deployments, please contact me, I would much prefer that solution.

Notes:

This is not platform-specific, behavior id dictated by the TCP spec

A nice description https://www.baeldung.com/cs/tcp-socket-no-connection-timeout

2 answers

Your answer

Tom Surace 0 Reputation points

2026-07-01T22:44:58.86+00:00

I have been seeing the same problem for ages. If the server just stalls, you will trigger the Request timeouts. But if the server is killed, or the connection is dropped by a firewall that rudely in a way that does not send a FIN packet to close the socket (more common than you think), request.GetResponse() will hang forever, when GetResultStream internally calls InternalGetRequestStream().Result (async), which calls Task.GetResultCore() which calls InternalWait with an infinte timeout. And, voila, you have an infinite hang. Before the .NET Core split this code had the same problem, so it seems likely the old school async code was just ported to new async syntax without fixing the timeouts.

My reading suggests that most OSs will time out the TCP socket at ~2 hours on a typical network stack with default timeouts. So... it might as well hang forever. Since GetResponse is stalled on retrieving the socket status and has no timeout, and the server never sends a FIN, the network stack thinks both servers are alive and must wait for one or the other to terminate the socket before it can clean up.

Just you know .. it's real. You'll really only notice if you're behind a rude corporate firewall. And before you point out that "they really should fix the firewall", yes, I know. If you are a VIP who can dictate IP filtering policy over all of our customer's IT deployments, please contact me, I would much prefer that solution.

Notes:

This is not platform-specific, behavior id dictated by the TCP spec

A nice description https://www.baeldung.com/cs/tcp-socket-no-connection-timeout

Answer 1

Boyd Mills 0

so..... It has to be wrapped in a try - catch structure?
Boyd

Yijing Sun-MSFT 7,106 Reputation points

2021-11-11T05:23:23.907+00:00

Hi @Boyd Mills ,
First,I think you could try to set HttpWebRequest.ReadWriteTimeout Property.And then you could use using outside the HttpWebResponse .
Best regards,
Yijing Sun

Answer 2

Jaliya Udagedara 2,856 MVP Volunteer Moderator

It won't return, if the resource is not returned within the time-out period, it will throw an exception of type WebException with the Status property set to WebExceptionStatus.Timeout.

Tom Surace 0 Reputation points

2026-07-01T22:46:34.96+00:00

The specific bug here is that the timeouts are not respected if for various reasons the underlying TCP connection is not properly closed but is also not functioning.