TCP connection timeout control

RouterOS General
1

I am attempting to learn the Microtik routerboard os, and have a fairly specific need at this time.

Here’s the scenario: I have a customer who has an older application server whose customers log on to their server using telnet. The issue they are having is with the tcp connection timeout in the client’s routers. Some will disconnect after 10 or 15 minutes of no activity, others will stay connected for longer.

I tracked it down to the TCP timeout, but of course not all routers will allow configuration of that setting. I am currently using a SonicWall firewall for testing purposes and can create a rule for the outgoing connection, and set the timeout for that connection only. I know it works as I can change the timeout and see the connection drop after no activity for the time I set.

However, I’m trying to find a less expensive solution. I purchased a RB750 for testing purposes, and have learned my way around the basics.

I know about the settings under the Firewall->Connections->tracking tab, but these do not seem to have any effect on the telnet session timeout, and in any case I do not see a way to set this parameter on a connection specific basis.

My customer has a large customer base, and I am hoping to be able to deploy multiple units if I can come up with a solid solution, but so far I have not been able to get the Microtik to even be able to end the connection, let alone to adjust the timeout.

Any help or ideas will be greatly appreciated.

2

is this related to the mikrotik unit? And not to the telnet server/client? the settings in connection tracking should actually work to adjust.

3

When testing previously with a sonicwall, I could set the tcp timeout to 60 seconds, enter the telnet command but just leave it at the login prompt, and 60 seconds later it would say “connection to host lost”. If I set the timeout to 600 seconds, same thing after 600 seconds.

The server is set to disconnect after 120 minutes, which it does reliably.

When using the microtik, the connection (ip->firewall->connections) times down with whatever time I have set1d it to, but the connection does not actually terminate when the time runs out. There is no “connection to host lost” message.

For clarity, I am looking at the “TCP Established Timeout” setting, and yes, the “enabled” box is checked.