Aug 272014
 

I have several Xen and KVM vps servers and they all suffer with the same problem of “nf_conntrack: table full, dropping packet” but its an easy fix

You can check what the current number of nf_conntrack_max is set to.
cat /proc/sys/net/nf_conntrack_max
the default is 65535 but all mine were set to 15000.

Now to increase the number of nf_conntrack_max
echo 100000 > /proc/sys/net/nf_conntrack_max
Now if you check again it should be the new value.

Now to make the change permanent we add the following to the bottom of /etc/sysctl.conf
net.nf_conntrack_max = 100000

Please note that the directory path to “nf_conntrack_max” differs between Linux distributions, the above works for CentOS

Jul 072014
 

Centos 7 has now been released to the public.

Release announcement can be found here http://lists.centos.org/pipermail/centos-announce/2014-July/020393.html
Release notes can be found here http://wiki.centos.org/Manuals/ReleaseNotes/CentOS7
The fastest way to download is via torrent, I’m currently seeding all images available and am pushing approx 300Mbps (megabits per second) across my servers and have done 200GB+ of bandwidth in under 3 hours.

I will be updating most of my servers over the next few weeks/months and will start updating my tutorials again, happy testing.