I've got 3cx running on Windows XP. Its been working for over 6 months with no issues and we're using Yealink phones, soft phones and Android phones. We decided to move the server to Windows7 so we created a new computer, installed 3cx and exported/imported our 3cx settings over to it. We gave it exactly the same IP settings as the old server. The only thing different was that on the XP machine, we could disable the Windows Firewall and it all still worked. When we attempted this on Win7, nothing worked. When we installed 3cx, the installer created some default firewall rules which we've added new rules to allow the appropriate traffic through (we've emulated our hardware firewall open ports in bound and allowed all traffic outbound). We've run the firewall checker and had 100% success in the results. There are not errors in the server event log. **Problem** When someone calls us from external, we can hear them, but they can't hear us. When we call an internal extension, we can hear each other (so the internal network is working). I've done a lot of research on forums and everyone keeps talking about ports and firewalls. My issue is, I've opened up more ports on the Windows7 server than I have on the hardware firewall and still no better. I started to doubt myself so I fired up another Win7 machine in VMWare and it got exactly the same issue. Has anyone got any ideas on this?