ARP Problems (Entires becoming Static)
Posted on 2006-10-28
Have a weird one here that I hope you can help me understand how and why the following would happen.
In a remote site, on one subnet, there are 8 machines.
All are MEANT to have connectivity to one another, and ideally they do.
However, one day, one machine (machine B) can contact all the other machines on this subnet EXCEPT for machine A.
Now, all machines other than machine B, can contact machine A.
From machine A, I can ping all other machines other than machine B.
From machine B, I can ping all other machines other than machine A.
What I found:
I jumped on to machine A, and issued the following command:
To display the arp table.
I found an entry in here for machine B that was type STATIC.
All other entries were dynamic.
I removed this static entry by:
arp -d <machine B ip address>
After this, I had connectivity back between machine A and machine B.
I know you can manually add a static entry in the arp cache for a system.
However, this has NOT been done in this case, and we dont have any need to do this.
So, my question is, under what circumstances, how, and why, would an arp entry for a machine become static if it was
NOT manually added to the arp cache as static. It really has got me stumped. Would a switch have something to do
Thanks in advance.