# How do i fix this (Neighbour table overflow)

## Xanthorax

My logs are being spammed with this

 *Quote:*   

> Neighbour table overflow.
> 
> NET: 637 messages suppressed.
> 
> Neighbour table overflow.
> ...

 

I ran 2.4.20-pre10-ac2 and i'm currently running 2.5.44-ac4. I have 3 ethernet cards (1x i82559 and 2x i82557) running using the e100 driver. I have changed the folowing kernel settings

 *Quote:*   

> echo "1" >/proc/sys/net/ipv4/ip_forward
> 
> echo "1" >/proc/sys/net/ipv4/conf/eth0/arp_filter
> 
> echo "1" >/proc/sys/net/ipv4/conf/eth1/arp_filter
> ...

 

2 of the 3 cards are on the same switch/lan, i'm using a special rule based routing table (using ip route2) to route traffic over the correct interface.

 *Quote:*   

> 0:      from all lookup local
> 
> 32765:  from <eth2-ip> lookup eth2
> 
> 32766:  from all lookup main
> ...

 

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## brain

Did a quick Google search and came up with this.   Sounds like it might be a problem in your ruleset preventing stuff from getting to localhost?   Just a guess.

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## Xanthorax

I think you are right, ifconfig shows me that not many packets are going over lo. This is my current config:

/etc/conf.d/net

 *Quote:*   

> iface_eth0="130.89.166.2 broadcast 130.89.191.255 netmask 255.255.224.0"
> 
> iface_eth1="10.0.0.1 broadcast 10.0.255.255 netmask 255.255.0.0"
> 
> iface_eth2="130.89.165.246 broadcast 130.89.191.255 netmask 255.255.224.0"
> ...

 

/etc/init.d/iproute2

 *Quote:*   

> ip rule add from 130.89.165.246 table eth2
> 
> ip route add 130.89.160.0/19 src 130.89.165.246 scope link proto kernel dev eth2 table eth2
> 
> ip route add 10.0.0.0/16 src 10.0.0.1 scope link proto kernel dev eth1 table eth2
> ...

 

ifconfig

 *Quote:*   

> eth0      Link encap:Ethernet  HWaddr 00:D0:B7:E8:9E:BB
> 
>           inet addr:130.89.166.2  Bcast:130.89.191.255  Mask:255.255.224.0
> 
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> ...

 

routing

 *Quote:*   

> chihiro / # ip rule list
> 
> 0:      from all lookup local
> 
> 32765:  from 130.89.165.246 lookup eth2
> ...

 

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## N-S

So, what did you do to fix this problem?

I use gShield firewall and using the same commands to check rules I got the following:

/etc/conf.d/net

 *Quote:*   

> 
> 
> # /etc/conf.d/net:
> 
> # $Header: /home/cvsroot/gentoo-src/rc-scripts/etc/conf.d/net,v 1.7 2002/11/18 19:39:22 azarah Exp $
> ...

 

/etc/init.d/iproute2

no such file.

ifconfig

 *Quote:*   

> 
> 
> ath0      Link encap:Ethernet  HWaddr 00:0D:88:81:8C:5B
> 
>           inet addr:192.168.3.101  Bcast:192.168.3.255  Mask:255.255.255.0
> ...

 

ip rule list

nothing happens

ip route show table local

 *Quote:*   

> 
> 
> broadcast 192.168.3.0 dev ath0  proto kernel  scope link  src 192.168.3.101
> 
> broadcast 192.168.2.255 dev eth1  proto kernel  scope link  src 192.168.2.101
> ...

 

added a few commands of my own

ip route show

 *Quote:*   

> 
> 
> 84.216.47.57 dev eth0  scope link
> 
> 172.16.1.33 dev tun0  proto kernel  scope link  src 172.16.1.34
> ...

 

hmmmm, doing " ip neig show" lists a LOT of addresses in the format of:

(an ipaddress here) dev eth0 lladdr (a MAC address here) STALE

oh, yes, I use rtorrent for torrents, btw. So I guess these ips are working on my torrents.

Next command:

ip ntable show

 *Quote:*   

> 
> 
> inet6 ndisc_cache
> 
>     thresh1 128 thresh2 512 thresh3 1024 gc_int 30000
> ...

 

ip tunnel show

 *Quote:*   

> 
> 
> sit0: ipv6/ip  remote any  local any  ttl 64  nopmtudisc
> 
> sit1: ipv6/ip  remote 64.86.88.116  local any  ttl 64
> ...

 

ip link show

 *Quote:*   

> 
> 
> 1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
> 
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
> ...

 

ip addr show

 *Quote:*   

> 
> 
> 1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
> 
>     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
> ...

 

Finally, here's my info

emerge --info

 *Quote:*   

> 
> 
> Portage 2.1.1_pre4 (default-linux/x86/2006.0, gcc-4.1.1, glibc-2.3.6-r4, 2.6.16-gentoo-r10 i686)
> 
> =================================================================
> ...

 

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## N-S

I followed the info here and it is now fixed.

https://forums.gentoo.org/viewtopic-p-3524450.html#1824201

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