-----Original Message-----
From: Paul Keating 
Sent: November 8, 2005 1:02 PM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Very ODD problem with NB5.1MP3a + 2 Solaris
Clients


yep, completely different subnets and routes, but for some reason, I'd
bet that when you try to do a backup, the client is trying to reply to
the server on the wrong interface.

I'll bounce it off my network guys.....I can't remember the details on
their side...I think one of the guys even did a powerpoint presentation
on it diagramming the traffic flows.

it is in essence a box problem...im my case, it was with a windows file
server, and an exchange server.

In both cases, there was "only one path to the backup server, and other
NICs but with separate interfaces+routes+subnets"


you showed that after you hit the backup server from the client, THEN
you could hit the client from the server....but for how long?
5 min? 10 min? 30 min?

figure that out, then ask your network guys what the ARP refresh rate
and CAM table timeouts are on the switches/routers.

this only happens with 2 of the 5 clients, correct? are they connected
to a different switch, or is their "non-backup vlan" different than the
ones that do work?

Paul


-----Original Message-----
From: Piszcz, Justin [mailto:jpiszcz AT servervault DOT com] 
Sent: November 8, 2005 12:35 PM
To: Paul Keating
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Very ODD problem with NB5.1MP3a + 2 Solaris
Clients


They are multi-homed but with completely different subnet masks and
routes.
Again, there are 5 machines with only 1 path to the backup server, there
are other nics but with separate interfaces+routes+Subnets.
 
I see what you are saying but this is a completely vlan+server-isolated
backup network.
 
I've checked with the network guys they are telling me is a box problem.
 
Any other ideas?
 
Justin.
 



From: Paul Keating [mailto:pkeating AT bank-banque-canada DOT ca] 
Sent: Tuesday, November 08, 2005 12:16 PM
To: Piszcz, Justin
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Very ODD problem with NB5.1MP3a + 2 Solaris
Clients
 
Ummm....are any of your systems multi homed?
 
looks like an asymmetrical routing issue we had here recently.
 
backup server talks to client on NIC A, but client replies back to
server from NIC B via an alternate path.
 
the ARP table on your switch that the backup server and NIC A are
connected to doesn't get populated with the MAC of the client NIC A
untill the client ARPs or tries to talk to via NIC A....then
communication works for 5-10 minutes or untill your ARP cache refreshes,
then communication is broken till the client tries to talk to the server
again.
 
I'm thinking it's likely not an issue if your clients all are single NIC
or connected to a single switch along with the backup server.
 
check with your network guys to see if they're seeing any broadcasting
on the switches your backup server and clients are attached to.
 
Paul