GRANT ALL PRIVILEGES ON *.* TO 'trevor'@'%' IDENTIFIED BY 'some_pass' WITH GRANT OPTION;

Now I can connect on the local machine with mysql -u trevor -p, and I can specify -h localhost or -h 127.0.0.1 and still connects. But if I use the host 192.168.0.105 (the machine's local IP address) or the host trevor.hopto.org which points to my IP address, I can't connect. It tells me ERROR 2003: Can't connect to MySQL server on '192.168.0.105' (111).

It sounds like a router/firewall problem to me, but I've combed through all of my router configuration and tried everything, and I still can't connect. Is it possible this is a MySQL problem?