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CME using SIP with a Watchguard firewall


Hope I can find someone who has experienced issues similar to what i have experienced.

I had 2 clients who are using CME and I moved them onto SIP with a Watchguard Firewall.


Outgoing calls always work find but inbound calls have always been an issue. Checked with the SIP provider and they always say that the IP address that they are receiving is the internal address as opposed to the external. On the watchguard we had to use SIP ALG initially to get calls atleast working but it always the issue was pointing towards that.


But with the Cisco ASA i have not had the issue.


The SIP Provider in the UK is Gamma. 


Has anyone experienced this issue and how did you resolve it. Is this a config issue on the CME.


Thanks in advance i can provide the configurations if required.



Please rate the post Shibly Ibrahim

This is not a CME/CUCM issue

This is not a CME/CUCM issue but an issue with your firewall. SIP packets embed IP addresses inside them. To properly NAT them, the firewall has to do a deep packet inspection and (if necessary) modification of the packet. Cisco ASAs can do this. You'll need to talk to your support partners for the Watchguard product as to how to achieve this (if it's possible at all) GTG
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