I'm trying to set up multi-path I/O connection between a SLES 11 SP2 server and a Dell EqualLogic SAN. Dell has a White paper called "Deploying SUSE Linux Enterprise Server with Dell EqualLogic PS Series Storage Arrays" and the first step is to bind unique IP addresses to two NICs and confirm that you can ping the EqualLogic SAN. I have a Dell PowerEdge R720 server with 4 NICs. The first NIC goes to the production network and NICs 3 and 4 go to the iSCSI network and Dell switches then to the EquaLlogic box. Whichever of the two NIC's I bind first can ping the EqualLogic without a problem. The NIC that is bound second can initially not ping the EqualLogic at all. After about 10 to 15 minutes of the srever being up, it can ping the EqualLogic as well.

I can use ifdown to shut down NIC 3 and NIC 4 then ifup to start it up. If I shut down NIC 3 and then NIC 4 then bring up NIC 4 first then NIC 3, now NIC 4 can ping the box and NIC 3 can't.

Dell whitepaper says to not proceed with loading their Multipath IO so I haven't attempted to load that yet.

I can't see any reason for this behavior. Does anyone have an idea why the first NIC bound will work but the second NIC takes over 10 minutes to respond to a ping?