Here's a simple IP command for fabs if you didn't already know how to do it
Code:
        internal class IPCommand : Command
        {
            public IPCommand()
                : base("ip", 6)
            {
            }

            protected override bool Process(Player player, RealmTime time, string[] args)
            {
                var plr = player.Manager.FindPlayer(args[0]);
                var sb = new StringBuilder(plr.Name + "'s IP: ");
                sb.AppendFormat("{0}",
                    plr.Client.Socket.RemoteEndPoint);
                player.SendInfo(sb.ToString());
                return true;
            }
        }