Ip_conntrack: table full, dropping packet

You can easily increase the number of maximal tracked connections, but be aware that each tracked connection eats about 350 bytes of non-swappable kernel memory!

To print current limit type:

# sysctl net.ipv4.netfilter.ip_conntrack_max

Output:

8192

To increase this limit to e.g. 12000, type:

# sysctl -w net.ipv4.netfilter.ip_conntrack_max=12000

Alternatively, add the following line to /etc/sysctl.conf file:

net.ipv4.netfilter.ip_conntrack_max=12000

The following will tell you how many sessions are open right now:

# wc -l /proc/net/ip_conntrack

Output:

5000 /proc/net/ip_conntrack