Clients that use the pre-installed operating systems already have their servers network pre-configured with a static IP addresses; there is no more need for any manual setup. If you, however, decide to upload your own custom ISO and install the operating system yourself, you will need to manually configure your network. In that case, you will need to set the netmask to 255.255.255.0 and the gateway to the same address as the IP address assigned to you but the last block replaced with just a 1.
For example, if you have been assigned the IP address 126.96.36.199, than your gateway is 188.8.131.52 and the netmask 255.255.255.0.
The DNS servers for all customers are 184.108.40.206 and 220.127.116.11.