Jeff S Wheeler wrote: > Dear list, > > I have a linux 2.4 box running zebra and acting as a default > gateway for > a number of machines. I am concerned about "Neighbour table overflow" > output in my dmesg. From some articles I've read on usenet, this is > related to the arp table becoming full. Most of the posters solved > their problems by configuring a previously unused loopback > interface, or > realizing that they had a /8 configured on one IP interface > and a router > on their subnet that was using proxy-arp to fulfill the arp requests. > This was true with some redhat release (unconfigured loopback). But as you realized, this is not your problem. > When the network is busy I've seen as many as 230+ arp > entries, but it never seems to break 256. Is this an artificial limit > on the number of entries that can be present in my arp table? No, it's just the default (guess: 254 ARP entries per NIC?). Had the same problem, one (err, actually two; different story) machine acted as default router for various /22 subnets on each of the 4 NICs. It was just massive ARP requests, as we got our networks from previously shut down ISP. I guess even unfulfilled ARP request take a slot in the kernel neighbor table. > If so, I > would like to increase the limit by to 2048 or so and give myself some > headroom. I am concerned that might slow down packet > forwarding, but I can probably live with that. After some googling, I found: echo 2048 > /proc/sys/net/ipv4/neigh/default/gc_thresh3
Up to now I found no drawbacks, "only" the kernel message is gone. > > Has anyone on the list encountered similar problems? If so, > is this the > approach you took to solve them or did you do something else? > > Thanks, > > -- > Jeff S Wheeler <[EMAIL PROTECTED]> Thomas -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
