If your Cisco IP Phone is not working and you are using NAT, you need to open up some ports:
- Incoming UDP 5060 -> Point to the phone
- Incoming UDP 16384-16484 -> Point to the phone
If you are running a UPnP capable router, this should be more then sufficient. You may not even have to set this last one. By the way: The Cisco 79xx series phones are defaulted to 16384-32766 (These are a LOT of ports, but I found that restricting their number to 16384-16484 works just fine).
If you keep on having problems, try opening the following ports and pointing them to your phone as well:
Incoming UDP 123 (NTP - Network Time Protocol, may not be necessary)
Incoming UDP 69 (TFTP - Should not be necessary unless your TFTP server is on the other side of your NAT)
(This is an except from the following article)
Last modified: Monday, 28 September 2009, 10:27 AM