Blocked Ports

[JJDinsay]

Trying to use TightVNC or PCAnywhere to establish remote control between a PC located within a LAN that is connected to the Internet via an ADSL connection and a PC that is outside it. I setup the modem to allow TCP/UDP ports 5631/5632 for PCAnywhere and TCP 5900 for TightVNC but the connection is not allowed. I understand that the modem IP changes due to the DHCP assigned by my ISP and I have someone on the inside of the LAN to tell me what the public IP is and I change my connection my connecting apps, but for some reason it just can't be passed. Any chances, that the ports are being blocked? Anyone manage to use PCAnywhere to remote control a PC in Thailand?