First try to connect on one of this nostale servers with TCP sockets :
DE: ip: 79.110.84.75, port: 4001
EN: ip: 79.110.84.75, port: 4000
FR: ip: 79.110.84.75, port: 4002
IT: ip: 79.110.84.75, port: 4003
PL: ip: 79.110.84.75, port: 4004
ES: ip: 79.110.84.75, port: 4005
CZ: ip: 79.110.84.75, port: 4006
RU: ip: 79.110.84.75, port: 4007
TR: ip: 79.110.84.75, port: 4008
You will need to use Crypto that MarsBounty gave you to encrypt the login packet then send it to one of the server
Try to get a response from the server and it will be a good start