VOIP PBX looses connection to SIP-server German VOIP Telekom



  • Hello!

    I have a customer that uses a VOIP-PBX behind a pfsense router (APU-Board) and this PBX is connected to the sip server of the german Telekom. I setup a port forwarding for port 5060 and in the beginning very thing went smooth. But every day the PBX looses connection to the sip-server or stun-servers and the customer can not do any phone calls nor could someone call the customer.

    I have another customer with nearly the same setup and no trouble with the VOIP-PBX - only difference is that that pfsense is at 2.1.? and the customer with trouble uses pfsense 2.2.?

    The supports man of the PBX told me I should increase the timeout of NAT entries. Is this possible with pfsene? And does it make sense? Seams to me it is an excuse, no solution.

    Bye



  • Yes it is likely the solution to the problem and udp Nat Timeout can be changed in the advanced options somewhere. Maybe it's change firewall to conservative.
    If you had control of your sip server you could also move to tcp or tls sip which has longer timeout than default udp.



  • But every day the PBX looses connection to the sip-server or stun-servers and the customer can not do any phone calls nor could someone call the customer.

    All 24h the German Telekom will cut the Internet connection to his customers, also the business customers!
    Could this be the problem?

    The SIP Server is at your ISP side and the STUN server is normally placed free in the Internet,
    likes a server at a hoster.

    The other way is the following, take a PBX appliance inside of the DMZ at the pfSense.