In most cases, your virtual servers networking will automatically be configured by means of either DHCP on KVM based services, or by VZCTL in the case of OpenVZ.

If you want to make use of our IP Failover or Anycast IP addresses, though, you'll have to manually configure your networking for both platforms.

While on the Networking tab of your virtual server, you can click the cog next to any of your IP addresses & select Network Settings to see that IP addresses netmask/bitmask, gateway, resolvers, etc.

Remember, do not set multiple gateway entries! This will cause connectivity issues for your virtual server!

  auto eth0
  iface eth0 inet static
       address 205.185.113.2
       netmask 255.255.255.0
       gateway 205.185.113.1 

• Netmask: 255.255.0.0
• Gateway: Do not set a gateway

  auto eth1
  iface eth1 inet static
       address YOUR_PRIVATE_IP_HERE
       netmask 255.255.0.0
       

• Gateway: 2605:6400:2:fed5::1
• Netmask: /48

  iface eth0 inet6 static
       address YOUR_IPV6_ADDRESS_HERE/48
       netmask 48
       gateway 2605:6400:2:fed5::1

• Gateway: 2605:6400:1:fed5::1
• Netmask: /48

  iface eth0 inet6 static
       address YOUR_IPV6_ADDRESS_HERE/48
       netmask 48
       gateway 2605:6400:1:fed5::1

• Gateway: 2605:6400:3:fed5::1
• Netmask: /48

  iface eth0 inet6 static
       address YOUR_IPV6_ADDRESS_HERE/48
       netmask 48
       gateway 2605:6400:3:fed5::1

If your virtual server has < 512MB RAM you'll likely suffer poor network performance due to strict default buffer sizes.

To get around this please add the follow to your /etc/sysctl.conf

net.core.rmem_max=16777216
net.core.wmem_max=16777216
net.ipv4.tcp_rmem=4096 87380 16777216
net.ipv4.tcp_wmem=4096 65536 16777216

Once you're done this be sure to sysctl -p to apply it.

These settings will automatically apply during restarts so you shouldn't need to cron/script anything else.