[cisco-voip] CUBE SIP behind NAT Router

[Andreas Sikkema]

Euan,

> The SIP messages are showing the local private IP address of the LAN (see
> below) gi0/0 address which the SP is rejecting. I have tried to bind the SIP
> messages to a loopback with the public address and it is now showing the
> correct address in the invites etc. but I am not seeing any replies from the
> SIP provider other than my invites out.

I think you need to enable or disable the SIP ALG functionality on
your Draytek depending on what the scenario is you're trying to solve.
See for instance
http://www.elantelecom.com/technical-assistance/disable-sip-alg-draytek/
(first result for me on googling "sip alg draytek")


Now why do suppliers continue to validate IP addresses in the contents
of SIP messages? For blackhats it's easy to fix that, for us good guys
it only adds to the problems of interworking while adding no value at
all.

-- 
Andreas Sikkema