SIP sending internal IP instead of Public

Question

Hi, 
 
 I have an issue where the UTM is not altering the sip header from a private IP to the public IP of the firewall. Instead it sends the private IP to the SIP provider and obviously this doesn't work. Are you even able to setup the UTM to edit the SIP header? 
 
 Thanks

Argo · Answer

Hi Joerg-ST, 
 Holger Gran is correct. 
 what you require is SIP ALG, usually a modern phone system is NAT Aware and can adjust the packet without getting a firewall involved. 
 As this can be temperamental. I have never used this as it usually causes issues. 
 The only article I can find is; 
 https://support.sophos.com/support/s/article/KB-000034975?language=en_US 
 It may well work, but have never tried it.

SIP sending internal IP instead of Public

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