Hello,

I'm trying to troubleshoot some networking issues I'm having between my Linux servers connecting to a server at another location after a Cisco ASA firewall has been installed at my location. I can make the connection work if I lower the mtu on the NIC (ifconfig eth0 mth 1000) - however that supposedly can break the local network if I don't set everything else's mtu to match. Supposedly I can use the iproute package (debian etch) to lower the mtu on a per-route basis, but it doesn't seem to work for me. Any ideas?

Thanks,
slacky

Are you sure that you can connect through Cisco ASA firewall only if MTU is lower then 1500. Try telnet.
If your equipment is connected to firewall by ethernet it should use MTU=1500, you do not need to change anything.

Well, my Linux server could not connect to a specific IIS web server through the Cisco ASA firewall unless I lowered the MTU on eth0. Windows 2000 or XP had no problem connecting through the ASA. However, after experimenting it seems to be a problem with the TCP MSS - which I can make work if I change as per:

Not really sure this is the best way to go - I think I might be better off seeing if this can be configured on the ASA as I do not have this problem if I don't go through it.

Thanks,
slacky