SLES 11 SP2 for VMware lose connectivity

SUSE Product Topics SLES Networking
21

OK, now happened again. I can’t tell anything out of it so I hope it makes sense to you. I’ll try to send it to you via private message.
[LIST]
[]08:57 - 10:05 pinging fine
[]10:05:49 redirected packet from 10.31.0.1
[]10:05:49 - 10:06:52 pinging fine
[]10:06:53 no replies from 11SP2 back to default or LMC gateway
[*]packet skipping, according to Wireshark, is now 16 (if I calculated correctly)
[/LIST]

22

Hi Timo,

I answered more detailed in a private message, but to sum it up for others following this thread:

  1. I saw some (to me) unexpected behavior of the ping client: The ICMP sequence numbers were not consecutive, but with varying increments although the request frequency was about 1Hz ( ;), make that one request per second) when responses were received, and 5 seconds when no responses were received. When I could see ICMP requests by the client going to multiple destinations, there was a +1 increment, thus I suspect the client has a system-wide request ID generator.

  2. The first ICMP redirect by the router was seen very late, 1000s of seconds into the trace.

  3. That redirect wasn’t honoured by the server immediately - it took 37 seconds until ICMP echo responses were sent to the LMC gateway instead of the default router!

  4. 27 seconds later, the server stopped responding to those specific ICMP echo requests (but answered others). That’s roughly a minute, could be an expiring redirect cache entry.

I feel that it’s the Linux ICMP redirect bug, referenced above in msg #4. And the “case of the vanishing ICMP echo requests”, aka “request id increments by 4”, seems to be just unexpected ping client behavior.

Regards,
Jens