Odd ARP problem...

[cpals]

I'm having a weird problem at work where we just installed our first HP blade setup and the blades can talk to EVERY server on our network except for this one server. It's very strange... they're all on the same VLAN and are connected via a Cisco 6509 switch.

I figured out that when I do a ping to one of the blades from the 'bad' rack server and then do an arp -a it shows:

IP 00-00-00-00-00 invalid

So somehow for this one specific server it's not resolving the MACs for our blade servers. I did put a static entry in the ARP table for the blade server's IP and am now able to ping the blade servers. However, the communication seems very sluggish and browsing shares, etc are very slow.

Only thing I haven't tried yet is to install the latest NIC drivers so that will most likely be next.

 

[drebo]

Try clearing the arp cache of the 6509. I've had this problem before with Cisco gear, where if I move an IP address from one device to another, the arp table doesn't get updated. It's probably not the same issue you're having, as it's only ever affected me on layer 3 interfaces, and it sounds like your communication is all on the same segment, but you might want to compare your arp table on your 6509 to what is actually on that segment.