A small hint: Don’t trust who say its GM/admin. WE DON’T NEED YOUR ACCOUNT NAME AND/OR PASSWORD! NEVER PROVIDE THEM!
Some Antivirus may react to L2.exe, because the process hides itself after beeing started in order to prevent cheating.(But it is no Virus) Just add it to your exception list or turn AV off while playing on Faction Server. If you still get problems whit connection.Check your hosts file or request support on forums.