Re: ARP Errors...

From: Duane Wessels (wessels@ircache.net)
Date: Fri Jun 23 2000 - 00:26:22 MDT


On Tue, 20 Jun 2000, Tim Eads wrote:

> Hello-
>
> I seem to recall reading somewhere on your site that there might be
> instances where ARP errors could occur when running a PolyGraph test.
>
> I believe I have encountered this in some of my testing with a Linux OS.
> During the test, I will get messages on the Linux box that say "neighbor
> table overflow". Is there a way to correct for this in Polygraph? Or,
> maybe increase the size of the Linux ARP table (Red Hat 6.0)?
>
> This might go beyond the scope of this posting, but any suggestions you have
> would be appreciated.

I found this in /usr/src/linux/net/ipv4/arp.c:

struct neigh_table arp_tbl =
{
    NULL,
    AF_INET,
    sizeof(struct neighbour) + 4,
    4,
    arp_constructor,
    NULL,
    NULL,
    parp_redo,
        { NULL, NULL, &arp_tbl, 0, NULL, NULL,
          30*HZ, 1*HZ, 60*HZ, 30*HZ, 5*HZ, 3, 3, 0, 3, 1*HZ, (8*HZ)/10, 64, 1*HZ },
    30*HZ, 128, 512, 1024,
};

The last three numbers (128, 512, 1024) are some kind of thresholds
on the table size. You might try increasing the values. I have
no idea what the negative consequences would be.

Duane W.



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