No Audio with IP iPhones but Works with Softphones - Incredible PBX & pfSense Firewall Setup

[sridharaon]

I'm currently experiencing a strange issue with my Incredible PBX setup. The setup is running behind a pfSense firewall. Here’s the problem I’m facing:

Issue: When making calls using IP iPhones (specifically, hardware-based SIP phones), there's no audio on the calls. However, when I switch to softphones on the same network, audio works perfectly fine.

Setup Details:

PBX Software: Incredible PBX
Firewall: pfSense
Softphone Software: Zoiper
Network Configuration: Both the softphones and IP phones are on the same local network.

I'm at a bit of a loss as to what could be causing the discrepancy between the softphones and the IP phones. Any insights or suggestions on what to check or adjust would be greatly appreciated.

Thank you in advance for your help!

 

[dallas]

We need a bit more information. Is the audio missing in both directions or just one way? What codecs are configured in the pbx? What ports are you using for the audio in the phone vs Zoiper.

 

[dicko]

Further, use sngrep to see what ports and addresses are being negotiated by SIP for the SDP session

 

[sridharaon]

We need a bit more information. Is the audio missing in both directions or just one way? What codecs are configured in the pbx? What ports are you using for the audio in the phone vs Zoiper.

Thank you for the quick response. The audio is missing in both directions. Here are the details:

Phone Codec: G.722, u-law, a-law
Zoiper Codec: u-law, a-law, GSM
Phone Local RTP Port: 5004
Zoiper Local RTP Port: 8000

Please let us know if you need any additional information.

 

[sridharaon]

Further, use sngrep to see what ports and addresses are being negotiated by SIP for the SDP session

Thanks for the suggestion! I'll use sngrep to check what ports and addresses are being negotiated by SIP for the SDP session and get back to you with the findings.

 

[Eliad]

where is the IncrediblePBX server, local behind the pfSense or the server is in the cloud?

 

[sridharaon]

where is the IncrediblePBX server, local behind the pfSense or the server is in the cloud?

IncrediblePBX server is installed in the cloud, hosted on a Proxmox virtualization platform.

 

[Eliad]

did you forward any SIP ports in pfSense? If you did, you should remove those, in this case pfSense should work on default settings. You port forward only when IncrediblePBX is local, behind the pfSense firewall

 

[sridharaon]

did you forward any SIP ports in pfSense? If you did, you should remove those, in this case pfSense should work on default settings. You port forward only when IncrediblePBX is local, behind the pfSense firewall

We haven’t forwarded any SIP ports in pfSense; it’s all on the default settings. With the same setup, we had Elastix PBX running without any audio issues. We are in the process of migrating to Incredible PBX and are encountering this audio problem now. Any advice on what might be different in this setup compared to Elastix would be greatly appreciated.

 

[Eliad]

We haven’t forwarded any SIP ports in pfSense; it’s all on the default settings. With the same setup, we had Elastix PBX running without any audio issues. We are in the process of migrating to Incredible PBX and are encountering this audio problem now. Any advice on what might be different in this setup compared to Elastix would be greatly appreciated.

i no longer have a pfSense. What i recall you might need to set the firewall to conservative and there is one more setting called preserve port or something like that, you might need to enable it. pfSense mangles the outgoing ports and you dont want that. Also, if you have the SIP-ALG package, you probably want to remove it. These changes could help. Maybe an expert will chime in and correct me if I am wrong.

 

[Samot]

Change the IP phones to use ulaw as the first codec. This is a codec negotiation issue.

 

[sridharaon]

i no longer have a pfSense. What i recall you might need to set the firewall to conservative and there is one more setting called preserve port or something like that, you might need to enable it. pfSense mangles the outgoing ports and you dont want that. Also, if you have the SIP-ALG package, you probably want to remove it. These changes could help. Maybe an expert will chime in and correct me if I am wrong.

Thank you for your suggestions. I’ll definitely check the settings you mentioned, such as setting the firewall to conservative mode, enabling the preserve port option, and removing the SIP-ALG package. I appreciate your help, and hopefully, these changes will resolve the audio issues.

 

[sridharaon]

Change the IP phones to use ulaw as the first codec. This is a codec negotiation issue.

I’ll try changing the IP phones to use ulaw as the first codec and see if that resolves the issue. Thanks for the advice!