Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

Cisco Employee

How do I check TCP TimeOut in CSM?

Hi, we have CSMs V3.2. I am curious what is the TCP TimeOut setup and if there is a way to adjust it?

Thx, Q.Xie

Cisco Employee

Re: How do I check TCP TimeOut in CSM?

there is an idle timeout per vserver.

The command to change it is 'idle ....'

To see the current settings, do a 'sho mod csm X vserver name ... detail'

There is also a pending timeout.

If the 3-way handshake does not complete within this time, the connection is dropped.

This time is adjustable with the command 'pending ...' [again, this is per vserver].



Thanks for rating this answer.

New Member

Re: How do I check TCP TimeOut in CSM?

We have an application that runs from an UNIX box to a web server which sits behind our CSM (configured in router mode). There is a default vserver which handles all traffic that does not otherwise match any rules. The inbound timeout is set to 600. This application is expecting an idle connection to stay live until it gets a reply from the web server that the job is completed. This may require the connection to stay open up to 4 hours. I know for a fact that we do not want to have all unhandled (rule base) connections open for 4 hours. Can you give me an absolute longest timeout that should ever be used? At the default, the CSM will fill up connection tables and memory in less than 1 day. Thanks for your reply.

Cisco Employee

Re: How do I check TCP TimeOut in CSM?

it all depends on your traffic rate.

The CSM can hold 1 million connections in memory at the max.

So, if you set the idle timeout to 10 hours, your max connection rate is 1 M / 10 * 3600 = ~250 conn/sec.

Assuming they would all be open and then idle.

There is no magic number here.

Try to find a limit based on the limit of the CSM and the connection rate that you see in your network.