SIP ALG

[bkoffler]

Hi -

I have seen some posts about this going back a few years, but i have a SonicWall TZ300 and i have been having issues for a while where i pick the phone up, but all i hear are bits and pieces of the oterson on the other side - i know someone is there, but i can't understand a word they are saying. Additionally, i am frequently getting voicemails which are blank, but go on for a while so i am assuming that something is happening to the audio there as well.

Whenever i do test calls to or from my PBX to other phones the calls work fine - but something is happing at other times.

I ran my firewall test and i am constantly receiving an error that SIP ALG is detected so i was thinking maybe that had something to do with the issue?

I configured my firewall exactly how the documentation states in terms of disabling IP transformations, etc..

Has anyone experienced any similar issues or have any ideas on what avenues i should explore? I have been having these audio problems for months on this system but now it is going to start getting more traffic and i need it working.

Please let me know your thoughts when you have a chance.

 

[SteveITS]

You should disable SIP ALG in your router. What kind of router is it?
https://www.3cx.com/docs/manual/firewall-router-configuration/#h.vbntni6x8gau

 

[Marconi]

Did you follow the SonicWall instructions on disabling SIP ALG (Link)? 3CX also have documentation regarding SonicWALL but it doesn't list the unit you have so I'd go with the instructions from SonicWALL.

Another thought: Are you running the SonicWALL behind another router? If you are then you need to disable SIP ALG on that router as well as on the SonicWALL. e.g.: ISP <==> Router 1 <==> SonicWALL

 

[bkoffler]

I think that is exactly what the issue is - my FIOS router has SIP ALG enabled by default and there is no way to disable it. I am going to see if i can eliminate it from my network, or get a replacement which allows me to adjust that setting. Thank you for putting that idea forward - i didn't even think of that!

 

[Marconi]

Thank you for putting that idea forward - i didn't even think of that!

Glad to help. Running 3CX through more than 1 router (called Double NAT) is always a problem because you have to make sure that both routers are doing the right thing.