I am running Asterisk on my internal network. And I had port forwarding of 5060 from public IP to my Asterisk's internal IP address. I have recently installed a few FreeSWITCH from git on remote locations. And the weird thing is whenever I am trying to register to those FreeSWITCH servers with a softphone on my laptop, the returning SIP message end up routed to the Asterisk instead of my laptop since my softphone default SIP port is 5060. But the same wouldn't happen if I am registering to remote Asterisk servers. The return SIP message will routed correctly back to my softphone. So in summary, I can register to remote Asterisk server even when I've already forwarded port 5060 to my internal Asterisk server, but I can't register to remote FreeSWITCH servers. Does anyone know the reason behind this? Henry