TCP keep alive packets dropped by the firewall

[Assafmil]

Hi,



We have started using the TCP keep alive mechanism.

Things are ok when the firewall is down.

When the firewall is active, the TCP keep alive packets are dropped by the firewall.

How can I configure the firewall to let the packets through?

The TCP ports change with each session so I can't simply open a port.



Thanks,

[Steven E. Protter]

Shalom,

Ask the firewall admin.

It would be helpful to know what kind of firewall we are talking about.

It may simply be blocking the ports you need in which case it needs to be configured to permit them.

SEP

[Assafmil]

The port is open and other TCP packets are passing ok.
It is a regular simple windows firewall.
The firewall log shows the specific packets that were dropped.

[Jim Keeble]

The firewall probably has an idle timer of some sort, where it stops passing a tcp connection if it is idle for that period of time. You might ask the firewall admin for that value.

Be default, the HP will wait for 2 hours before sending the first keepalive . You can reduce that by setting the ndd parameter tcp_keepalive_interval. The default valus is 7200000 milliseconds (2 hours) . To set it to 10 minutes, use :

ndd -set /dev/tcp tcp_keepalive_interval 600000

Hope this helps.