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Cat6509 - ARP Issues on Same Vlan

All servers are on the same Vlan. Some servers are having trouble seeing others on same Vlan. Pinging other servers on same Vlan always returns a "request timed-out" for the first reply. This 6509 is running native IOS ver 12.1(2)E. All servers have the correct IP, subnet, and gateway information. Any suggestions?


Re: Cat6509 - ARP Issues on Same Vlan

I would be looking for a host with a dup ip or a rogue answering arps that are not his. Look at the arp tables for a problem destination ip from several souces and see if they all have the same entry. If they dont have any entry ping it and check again. Then ping again and see if the arp entry is changing.

New Member

Re: Cat6509 - ARP Issues on Same Vlan

If the first ping time-out, this means that ARP is trying to learn the MAC address of the pinged device, usually this happens once unless the ARP cache is being flushed. What is weird here is that the servers are on the same subnet and the default gateway (router/L3) does not need to ARP for the destinations device.

The only logical explanation is that the servers are busy.