Network hangs...

Hi to all listmates, i manage a remote suse 7.2 server (full patched) with apache/tomcat. Today it was unreachable (no ping no ssh no http). I called my isp, he gone to console and told me: - memory was ok - the ip was up (ifconfig) - the route too - he wasn't able to ping any external ip (100% packet loss). I told him to start/stop network and route and all worked again... what's happened? /var/log/messages tells nothing of strange... Could somebody tell me what i can check to try to understand the reason of this strange behaviour? Is there a way to enable a more accurate log for the next time? Thanks a lot! Mario Libraro