See here: http://www.terrariaonline.com/threads/multiplayer-server-help.20436/ Has anyone checked to see if the 'new' server application (TerrariaServer.exe) is blocked by a Firewall? What people seem to be missing here is that there's now two ways to launch the same server via different programs. The old, or normal way, through the game (Host and Play) and now via the new way, by launching the TerrariaServer.exe file (the dedicated command line server). If the server operator hasn't added the new one (TerrariaServer.exe) to be excepted in their firewall, then it's not going to let anyone connect. On a side note - Assuming that this is actually a coding issue, if you guys want the Devs to take this seriously, you need to start troubleshooting and providing information that would actually prove this is a coding issue. You're going to have a hard time convincing them that their application is broken when a ton of other people are hosting and playing on the new server (over Hamachi or otherwise) fine. Simple logic, if it works for people who seem to know what they're doing, whereas the people reporting issues don't seem to, then where do you think they're going to assume the problem is? Don't mean to be harsh, sorry, just trying to put this into perspective for you. You need to help them, to help you, ya get me? Maybe I need to write up a troubleshooting guide..