[lvs-users] ipvsadm and packets leaving a gre tunnel

Marco Lorig mlorig at gmx.net
Sun Aug 3 22:28:50 BST 2008


From:  Joseph Mack NA3T
>we may have talked about this before but have you tried setting the mtu >on
the realserver's NIC? You only need set it for the route RIP:22->0/0, >but
setting it (or mss) for the nic will at least see if this method handles the
problem.

This works. Setting up a fixed mtu to the realservers default route (e.g.
1400) fixes the problem.
In other words: If the realservers send packets, which are small enough to
fit into the gre tunnell, everything works fine. 

I can demonstrate this by loggin in from the client to the server via ssh.
It´s possible to login and work with the shell (small tcp packets) but if
you do a "ls -la" in /etc for example (causes a tcp packet which is too big
for the GRE) the connection freezes.

Marco





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