Showing results for 
Search instead for 
Did you mean: 

sdp-anat on CME with 9971 SIP

Frequent Contributor
Frequent Contributor

I have several 9971 phones running SIP and working well on a CME 8.6 system. The CME also has plenty of SCCP phones running on it. I recently tried to add a 9971 phone that connects to the CME via VPN so therefore it is coming from a non-local subnet.

There is no firewall and no NAT involved. The phone registers but cannot call to any extension.

Doing a debug I basically see this: INVITE from 9971 require: sdp-anat from CME 420 bad extension unsupported: sdp-anat Why does the phone think it needs NAT? How do I tell the phone to not require this, or conversely, enable it on the CME to make the phone happy?

Thanks, Diego

22 Replies 22

Frequent Contributor
Frequent Contributor


I am happy to report the problem is fixed and it turned out to be tftp!  What was happening was that on the CME I had "ip tftp source-address loopback0" which points to the CME/CUE 10.1.10.x/30 subnet and this subnet was not being routed on the VPN.

What made the issue hard to track down was that when the phone was outside the office it could not download the CNF file but I it had enough configuration information to register on the CME thus leading us away from the real problem. 

Another thing that made it difficult was that using CME debugs the tftp appears to be working as far as the CME is concerned. The CME receives the request and sends the file but the phone does not receive the file. The phone status is where I realized that the phone was not receiving the CNF file.

I would not have expected the phone to be able to register without the CNF but I guess there is some caching going on??

Anyway, I changed the tftp source to be VLAN1 and the phone works on the VPN, video and all.

I have found that several features available on SCCP phones that do not show on the SIP phone.  For example the directory comes up empty and I don't see how to setup buttons for "silent" and "monitor" as you do on SCCP phones.

And it looks like I will have to setup duplicate DNs, so I can use the same extension on both SCCP and SIP phones!  Can that be correct?

Thanks for all your help.


Great to see this resolved.

I remember posting earlier that config file probably cached because ANAT for 9971 isn't supported by CME and probably the phone was registered with CUCM earlier which has ANAT enabled.

Regarding shared DNs for SIP and SCCP, yes you need to create voice register dn and ephone-dn with same number. If you want to have both ringing at the same time, you need to put the command shared sip on ephone-dn and shared max # on voice register dn.

Note: Shared DNs between SIP and SCCP started from CME 9.0 and its bit flaky. Some times you need to reboot the box to get it working.

Wow, I am on 8.6.  How can I find which features are supported for SIP phones?  Like the button types and directory, etc? 

Best  to look at cme admin guide. It will show all features and start release. Its always up to date

Will do.  Again, thanks for all your help.


Why are you dialing the number 2 - this seems a bit short....?

Frequent Contributor
Frequent Contributor

Yes, that is strange.  I am pretty sure that wasn't happening when we first started troubleshooting.  Right now I can't get the phone to register so once I get it back to registering I will keep an eye on that.


He won't be dialing two but this is how kpml works. First digit will be sent in INVITE message and reset of digits will be sent in NOTIFY messages (one message per digit).

The problem that cme is rejecting the first message because of anat.

Now I am interested to see the debugs during registration

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Recognize Your Peers