Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Sip-ua can't send public address

I have a 827-4v that have a ADSL modem broke.I have a 837 that are a gateway of my network.The problem is that a sip-ua agent send a private IP of 827-4v for authenticate whit an external SIP this :


Contact: <sip:0861XXXXS@>

Expires: 3600

the sip-ua are configure in this mode :

authentication username 08611XXXX password XXXXXX

nat symmetric role passive

nat symmetric check-media-src

aaa username proxy-auth

retry invite 4

retry response 3

retry bye 2

retry cancel 2

registrar expires 3600


The 837 gateway router have a static NAT like this :

ip nat inside source static udp 5061 interface Dialer0 5061

ip nat inside source static udp 5060 interface Dialer0 5060

I have read every thing about a SIP NAT etc but I do know what I have to do!!!


Re: Sip-ua can't send public address

sip:0861XXXXS@ was what was sent, however this is not a valid SIP address as SIP addresses are supposed to be in the form of user@host. Because it is an invalid address the phone most likely reuses the previous

contact info.

New Member

Re: Sip-ua can't send public address

Thank you but I know and I write this!

The problem for me is a configuration of the 837 (the gateway of my network) for SIP transparent NAT.

This for give a chance at a 827-4v to keep a valid pubblic addres to send in authentication.

Hall of Fame Super Gold

Re: Sip-ua can't send public address

Which IOS do you have on the 837?

Do you have access to IOS downloads to upgrade to latest image ?

It should replace the private address with the public one.

New Member

Re: Sip-ua can't send public address

The IOS is c837-k9o3sy6-mz.124-5b.bin

I have a smartnet for upgrade the latest IOS image.

I have just 1 pubblic address and is for 837.

The solution will be this ? :

the " Hosted NAT Traversal for Session Border Controller " .

If yes I can try to upgrade my flash and download the c837-k9o3sy6-mz.124-15.T1.bin IOS flash image that have this feature.

If not....I don't know what I have to do...may be use the 837 like a modem for 827-4V ?

CreatePlease to create content