arp cache and arp requests

[John Waller]

Hi,

Quite a simply question really.

I have a situation at the moment where by RDT's (Radio Data Terminals) keep crashing on an IBM RS6000 (P series) running AIX. Reading through IBM's AIX documentation it appears that AIX sends an ARP request every 20 minutes to every device connected over TCP/IP wether it has been idle or not. The problem with our RDT's is that some of these requests appear to be going missing so the arp cahe entry on the IBM is being lost causing communications to hand and eventualy fail.

The question is , Does HP-UX do the same kind of thing. We have a number of HP-UX systems but only the one IBM. Since we don't have problems with HP-UX I don't believe it does but I can't find any information about it on the HP web site.

[John Bolene]

On HPUX, from what I have seen, it only fills in the arp table when it connects to a device, it does not poll every once in awhile.

Sometimes we will get bad arp cache entries when a router gets rebooted with changes and we have to manually delete arp cache entries on some servers.

check man arp

[John Waller]

John, Many thanks for the response. I am familiar with the arp command and have had to delete entries and make static entries in the past. Its just since I found this info on AIX it has started me wondering whether AIX is on its own or other Operating Systems do the same thing. If anybody else can comment on other Systems, e.g. NT, Windows 2000, OS/400, Linux etc. and arp behaviour it would also be helpfull