Put Public IP in SIP VIA Header

[XwareInnovations]

i am using 3cx 16.0.6.655
and i am using peace communications as the sip provider.
if i enable the Put Public IP in SIP VIA Header option (yes its the correct ip) i can make outbound calls. but inbound calls do not work.
if i disable the option inbound calls work but outbound do not!. (because its using the local ip in the packet) so outbound calls return a 403 forbidden.

what i do not understand is why inbound calls do not work with this option turned on?

any advise?

 

[XwareInnovations]

for what its worth enabling sip alg on my firewall solves the problem. why does 3cx say that it should be disabled?? what issues should i keep an eye on with sip alg enabled?

 

[cobaltit]

Is Peace a 3CX supported provider? If not you should be asking them why it doesn't work.

As far as what you should look for, it's pretty obvious. Calls that don't work.

 

[JohnS_3CX]

Hi,

Since you are not using a supported provider, you will have to work with them for a solution. They can tell you what their requirements are, and then you have various options your can tweak in your 3CX trunk settings.

SIP ALG will attempt to modify SIP packets in order to "fix" problems, but there's no knowing what it will end up doing. Ultimately it's a black box that can either fix or break communications (sometimes it may do both simultaneously as weird as that sounds).

We prefer to not rely on such variable mechanisms, and instead know exactly what your provider wants, and in which fields it expects to find the various SIP values. This is why we recommend using an 3CX supported providers. These providers have been tested with 3CX, and pre-configured templates are included in 3CX that make configuration quick and easy. Both the provider and 3CX have committed to fully supporting the combined solution.

https://www.3cx.com/partners/voip-providers/