Cisco IP Phone NAT

[Abdu]

Hi

I have CME with two IP Phone

IP Phone1: 172.16.15.5

CME: 172.16.15.6

IP Phone2: 10.10.10.2

IP Phone2 have 10.10.10.2 and after NAT have 172.16.15.8, the problem I faced is the phone 2 can ring but not receive any Media only send, 

How I make Phone2 receive the RTP Media?, 

Thanks

[Vivek Batra]

Hi,

I suspect that it is working not because of STUN. Asterisk supports symmetric RTP and it must be relaying RTP traffic instead of establishing RTP directly between the end points. What symmetric RTP means that Asterisk ignores the SDP contents and sends the RTP traffic to NATted IP and Port instead of what is conveyed in SDP. 

Not only Asterisk, this behavior is common with any standard SIP based PBX.

I am sure this will never work with CUCM as CUCM will never relay RTP through it (unless MTP is being used).

Not sure with CME, will have to lab up and see how it reacts.

- Vivek

[Abdu]

actually i am using CME...

[Ahmed Khalefa]

Hello Abdul-Majeed,

can you tell me if you reached any success ?? ..

Ahmed Salah