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VoIP through a Firewall (NAT)

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  • #26862
    Mat @ Blue Lava

    I get a lot of questions regarding VoIP equipment running behind firewalls and I know it is a common problem faced by lots of you. This causes lots of problems like one-way speach, cannot register with the GateKeeper etc.

    I have listed some of the ports that you must open on your firewall to be able to start using VoIP – please note that this is far from a definitive list and certain vendors use different ports for proprietary signalling – but it should give you a head start !!

    Port 23 TCP – Telnet – For CLI type functions
    Port 80 TCP – HTTP – For Web browsing your gateway
    Ports 161 & 162 UDP – SNMP – If you monitor your GW via SNMP
    Ports 9002 & 9003 TCP – CDR – Used on a Quintum for sending the CDRs
    Port 1718 UDP – RAS – Used for GateKeeper discovery
    Port 1719 UDP – RAS – Used for GateKeeper registration
    Port 1720 TCP – Q931 – Used for Call Signalling (Essential)
    Ports 2000 to 2063 TCP – H245 – Used for H245 inter GW communication

    I hope that this information proves useful and hope that people add to the list with any vendor specifics.

    If you have any questions please feel free to contact me at:



    In addition to this I want to add a URL that will help Quintum users to configure their gateways behind NAT.

    Look for the following topic:
    Important document describing how to configure Firewalls and NAT, including NATAccess (80 KB PDF)

    Good Luck!


    Before doing all this, I would suggest putting tenor in DMZ mode and then try. I wonder if opening ports, though a possible solution, will work full fledge.

Viewing 3 posts - 1 through 3 (of 3 total)
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