On Wed, Mar 12, 2008 at 10:12:19AM +0530, Indunil Jayasooriya alleged: > Hi, > > I am getting below error on mailgw. it has 2 ethernets. > eth0 is connected to internet, while eth1 is connected to LAN where > there are about 300 PCs. > > > Mar 12 09:14:00 gateway kernel: NET: 697 messages suppressed. > Mar 12 09:14:00 gateway kernel: Neighbour table overflow. > Mar 12 09:14:05 gateway kernel: NET: 660 messages suppressed. > Mar 12 09:14:05 gateway kernel: Neighbour table overflow. > Mar 12 09:14:10 gateway kernel: NET: 682 messages suppressed. > Mar 12 09:14:10 gateway kernel: Neighbour table overflow. > Mar 12 09:14:15 gateway kernel: NET: 700 messages suppressed. > Mar 12 09:14:15 gateway kernel: Neighbour table overflow. > > Mar 12 09:14:20 gateway kernel: NET: 633 messages suppressed. > Mar 12 09:14:20 gateway kernel: Neighbour table overflow. > > > it happens very often. I goolgled and found some info. > > many talk about below file > > /proc/sys/net/ipv4/neigh/default/gc_thresh1 > > I increased its value to 300 > > But, i still get the same error. The "default" is only applied to devices as they come up. You'll need to also increase the values in the interface-specific directories. Be sure to also adjust your /etc/sysctl.conf because manually playing in /proc won't survive a reboot. In my very large flat network, I have the following in /etc/sysctl.conf: net.ipv4.neigh.default.gc_thresh1 = 4096 net.ipv4.neigh.default.gc_thresh2 = 8192 net.ipv4.neigh.default.gc_thresh3 = 8192 net.ipv4.neigh.default.base_reachable_time = 86400 net.ipv4.neigh.default.gc_stale_time = 86400 These are documented in arp(7). -- Garrick Staples, GNU/Linux HPCC SysAdmin University of Southern California Please avoid sending me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available URL: <http://lists.centos.org/pipermail/centos/attachments/20080311/10d86010/attachment-0005.sig>