[clug] "Neighbour table overflow" - not solved yet...

[Duane Voth]

on Tue, 28 Oct 2003 17:27:04 Matthew Hawkins wrote:
> I started playing with increasing these cache sizes until I maxed one out
> and still had the neighbour table overflow problem (albeit it took a lot
> longer to occur) and the dud route was discovered.  Fixing the real cause
> solved the issue.

and what *was* the real cause?  A bogus route?
Can you elaborate?

I'm having the same problems but my routes have not
changed for years.  The only significant change was that
I installed a new version of Linux (2.4.22) on three
of my machines.  Only one of these reports the Neighbour
table overflow problem.  This machine also exhibits
"traffic congestion" for a few seconds when /var/log/messages
receives these log messages.  Last of all, despite there
being a correctly registered dhcp and named entry for this
machine, ssh now rejects attempts to login to my firewall
(also a Linux box but which has been running for near a
year on 2.2.2x kernel) from this machine - as if some
authentication test is failing.  Some of these symptoms
may be related.

My routes are:

box4# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.0.0     *               255.255.0.0     U     0      0        0 eth0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo
default         box1.fufu.net   0.0.0.0         UG    0      0        0 eth0


There is at most 8 machine on my net at one time.

box4# arp -a
box1.fufu.net (192.168.0.254) at 00:40:37:D3:2F:F0 [ether] on eth0
box2.fufu.net (192.168.0.249) at 00:00:23:C3:D2:D6 [ether] on eth0
box3.fufu.net (192.168.0.100) at 00:E0:24:55:9A:BA [ether] on eth0

Not much of a crowd here...

...
Nov 14 17:16:32 box4 kernel: NET: 22110 messages suppressed.
Nov 14 17:16:32 box4 kernel: Neighbour table overflow.
Nov 14 17:16:32 box4 last message repeated 9 times
Nov 14 17:16:37 box4 kernel: NET: 44304 messages suppressed.
Nov 14 17:16:37 box4 kernel: Neighbour table overflow.
Nov 14 18:01:00 box4 CROND[8112]: (root) CMD (nice -n 19 run-parts /etc/cron.hourly)
Nov 14 18:36:51 box4 kernel: NET: 20092 messages suppressed.
Nov 14 18:36:51 box4 kernel: Neighbour table overflow.
Nov 14 18:36:51 box4 last message repeated 9 times
Nov 14 18:36:56 box4 kernel: NET: 43640 messages suppressed.
Nov 14 18:36:56 box4 kernel: Neighbour table overflow.
Nov 14 19:01:00 box4 CROND[8151]: (root) CMD (nice -n 19 run-parts /etc/cron.hourly)
Nov 14 19:57:11 box4 kernel: NET: 20858 messages suppressed.
Nov 14 19:57:11 box4 kernel: Neighbour table overflow.
Nov 14 19:57:11 box4 last message repeated 9 times
Nov 14 19:57:16 box4 kernel: NET: 42397 messages suppressed.
Nov 14 19:57:16 box4 kernel: Neighbour table overflow.
Nov 14 20:01:00 box4 CROND[8190]: (root) CMD (nice -n 19 run-parts /etc/cron.hourly)
...

By the way, the all knowing Google says you guys are the
closest ones to the answers on this issue.  ;)

Duane