Low volume on VoIP connections between lans (only on one way)

  • Hi,

    I've two lan networks on my pfSense box and i'm trying to route the VoIP traffic between both. For now finally i've opened all ports but i've seen an strange behaviour. My configuration is:


    • VoIP Phone
    • VoIP Server


    • Computer with VoIP software

    The phone and the Computer are connected to VoIP Server.

    The strange problem is that the sound from VoIP phone to Computer is very low, but from Computer to Phone is fine.
    If both are in same network then the sound volume is normal.

    Ive tried to add a rule to allow all traffic between both networks to check if maybe i've forgotten any port but i've the same problem.

    Someone knows what can be the problem?

    Greetings and Thanks!!

  • I would encourage you to look elsewhere for the problem.
    RTP, the packets handling the voice cannot affect the volume level unless something is re-coding the packets after processing the audio, and pfSense certainly does not!

  • Thanks for the info,

    That's what i thought, but i'm new in VoIP and then i was not sure because there is not any other thing between source and destination, and i thought that maybe was other problem like package lost.
    Maybe the VoIP server detect the network change and reencode the audio. Strange too but is the only thing that comes to my mind.


  • Lost packets will result in distorted, choppy or bad quality audio, but won't affect the volume.

  • Well, finally seems to be fixed "magically". On last friday I left the firewall configured and with the problem exposed above. Yesterday I did a test to continue trying to fix the problem and bingo… is working fine. Anyway tomorrow i've to do another test to see if still working.

    greetings and thanks!!

Log in to reply