SLES11SP3 can't connect to ONE sever


We have a problem in SLES11SP3.
Our server runs normaly. But sometimes we have a network error. The server can connect to every server and client in our network except for one other SLES server. Thats not always the same server. The traceroute from the other server to our server goes normaly until our gateway. Our server didn’t answert. A traceroute from our server to the other server, brakes direct on our server. A traceroute to every other server is normal, no problem.
This problem occurs every 4-6 weeks.
The firewall on server is disabled. AppAmor on server is disabled. The logs shows no error or warnings for this problem.
After a restart of the server, everything is normal.

Who can help us?!

Get a LAN trace of both sides, taken simultaneously, of the various tests
you try, particularly the traceroute stuff (as that is not
service-specific). The firewall should not matter (unless you’ve tweaked
it to block ICMP in traceroute’s case). The following, to be run on each
system, should capture a LAN trace to /tmp/ in a file named for the system
(to avoid duplicate filenames when posting them somewhere):

/usr/sbin/tcpdump -n -s 0 -i any -w /tmp/$(hostname).cap -v

Good luck.

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on next error i will try it.