I have  dedicated servers all over the world and most of them uses Xen based virtualization. For a while there is a network problem on vservers. High numbers of packet loss all of the vservers at high loads. By the way Xen servers controlled by SolusVM and there seems to be a problem with Xen. I have searched for this but there is no good answer for packet loss. I have checked system messages with dmesg and it gives me output like this:

ip_conntrack: table full, dropping packet.
printk: 188 messages suppressed.
ip_conntrack: table full, dropping packet.
printk: 179 messages suppressed.
ip_conntrack: table full, dropping packet.
printk: 183 messages suppressed.
ip_conntrack: table full, dropping packet.
printk: 178 messages suppressed.
ip_conntrack: table full, dropping packet.
printk: 209 messages suppressed.
ip_conntrack: table full, dropping packet.
printk: 173 messages suppressed.
ip_conntrack: table full, dropping packet.

This is the problem. ip_conntrack value is full and don’t allows new connection. I have increased the value and problem  solved
You can increase the value too. Here how you can solve this.

First of all you can check the max value of ip_conntrack and how much uses it now.
For the max value:

cat /proc/sys/net/ipv4/ip_conntrack_max

For current usage:

cat /proc/sys/net/ipv4/netfilter/ip_conntrack_count

I think you will see same number or nealry same to max number.
You can change it to higher values.

echo 131072 > /proc/sys/net/ipv4/ip_conntrack_max

131072 is not a limit you can increase it to how much you want. 2x of  old value would be good.

You can see your problem is solved now