On Mon, Jul 12, 2010 at 11:25 PM, Patrick Geoffray <patr...@myri.com> wrote: > Rahul, > > On 7/13/2010 12:04 AM, Rahul Nabar wrote: >> >> I am puzzled by a bunch of ARP requests on my network that I captured >> using tcpdump. Shouldn't ARP discovery requests always be sent to a >> broadcast address? > > No, the kernel regularly refreshes the entries in the ARP cache with unicast > requests. If that fails, then it sends the expensive broadcasts.
Thanks Patrick. I wasn't aware of this. I guess it makes sense now that I found the correct section of the RFP (http://tools.ietf.org/html/rfc1122#page-22). I see the converse situation too: Some ARP replies are being sent to a broadcast domain instead of a single MAC. Is that normal too? 00:26:b9:58:e5:9f > ff:ff:ff:ff:ff:ff, ARP, length 60: arp reply 172.16.0.29 is-at 00:26:b9:58:e5:9f 00:26:b9:56:38:71 > ff:ff:ff:ff:ff:ff, ARP, length 60: arp reply 172.16.0.14 is-at 00:26:b9:56:38:71 I'd have (naively) expected these replies to go to the specific MAC which had issued an ARP request on 172.16.0.29 or 172.16.0.14. -- Rahul _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
