SIP ALG + static port forwarding 5060

[CHKoehoorn]

Greetings,

I have a question that maybe someone can answer for me. Currently we are using a Cisco 1941 in combination with a VoIP PBX. In our standard configs we are using the following 2 lines to regarding VoIP operation:

- no ip nat service sip udp port 5060

- ip nat inside source static udp 192.168.11.246 5060 interface Dialer1 5060

The question is (hopefully) simple to answer and goes a followed:

Is it still required to disable SIP ALG (no ip nat service sip udp port 5060) when you also make a port forwarding for 5060 like discribed above. Isnt it so that forwarding 5060 1-on-1 is basicly the same as disabling SIP ALG? Or do they differ from one another? 

Im looking forward to the answer.

With kind regards,

Kees

[Philip D'Ath]

SIP ALG breaks lots of things on many platforms.  It solves a problem that has not needed solving for quite some time.  So definitely turn it off.

1:1 NAT is when you map an entire IP address to another IP address.  You above config is not doing this.  It is mapping an individual port to the same port on another IP address.