Receiving an 'ip_conntrack: table full' error.

On OpenVZ/HyperVM machines sometimes the ip_conntrack table will become full and drop packets. You can tell if it is doing this by looking in your /var/log/messages file.

To find out the current limit run:

sysctl net.ipv4.netfilter.ip_conntrack_max

Then to increase it edit:

/etc/sysctl.conf

and change the line:

net.ipv4.netfilter.ip_conntrack_max = to a higher number

Adding 5000 or 10000 to the current max should be fine.

Once you have saved the file, to reload the new configuration run:

sysctl -p

You should be all set and the machine should not be dropping any packets.