07-10-2017 07:41 AM - edited 03-17-2019 10:44 AM
Hello,
I have a Cisco IP phone 8811 (SIP) which is behind a Cisco 2821 router. This phone NAT's to public IP on Cisco 2821 and then registers to a CUCM on internet. When it registers, CUCM has phone's private IP address instead of Public. I think the problem is that Cisco 2821 is not able to do SIP ALG for Register request that phone send to the CUCM. I see phone sends a SIP register message which is TCP and sent to TCP port 5060 to CUCM. When I try configuring SIP ALG on Cisco 2821, it gives me an option to configure the SIP NAT service only for UDP port.
Is there any other way I can make Cisco 2821 to do SIP ALG on TCP 5060? If not, is there a way I can configure the phone to send the SIP register message on UDP 5060 instead of TCP?
From Cisco 2821 (does not give me a TCP option):
(config)#ip nat service sip ?
udp UDP protocol
Thanks!
07-10-2017 07:58 AM
Please do not post duplicate threads
https://supportforums.cisco.com/discussion/13328191/help-cisco-8811-sip-behind-nat-registering-cucm
07-10-2017 01:11 PM
Since I did not get any response on that thread I wanted to post it on this board to get some help and feedback.
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