The 3CX Firewall Checker Client Application Helps Troubleshoot Remote Extensions

The 3CX Firewall Checker Client Application helps to test the firewall that sits in front of a 3CX Phone system, but also the configuration of the PBX itself. This is useful for when the 3CX Firewall Checker within the Management Console succeeds all tests, but remote clients still present issues. The 3CX Firewall Checker Client Application helps to determine if this is a network, firewall, or other issue.

3CX Firewall Checker Client Application

Using the 3CX Firewall Checker Client Application

Download the 3CX Firewall Checker Client Application: http://downloads.3cx.com/downloads/3CXFirewallCheckerClientApplication.zip

Note: The Firewall Checker has to be run from a properly configured remote environment.

For the client to work with its default settings the following ports need to be open:

SIP Port UDP: 5091
RTP Ports UDP: Range 11000 – 11015

  • Unzip the downloaded file and run “RemoteConnectionTest.exe”.
  • Provide following details:
    • The external IP adress or FQDN of the 3CX Phone System and the SIP port in the following format: x.x.x.x:SIPport
    • Optional: Proxy Server IP Address.
    • STUN Server: Use default “Use SIP server as STUN”.
    • The extension authentication details (This can be an existing extension or an extension created for testing purposes).
  • Click “Start Test”.

The steps that 3CX Firewall Checker Client Application takes are:

  1. Resolves the FQDN.
  2. Sends a STUN request to the 3CX Server.
  3. Tries to register to the PBX using the extension authentication details provided.
  4. Makes a one minute call to the echo test System Extension (*777) and analyses if RTP packets are received.
  5. Makes a call back test to the System Extension (*888) and analyses if inbound call and audio packets are received.

3CX Firewall Checker Client Application Pass

 Further Reading

Liked this article?


Get notified of new articles
or share
You might also be interested in:
  1. Mahomed

    Great idea! I wish I’d know about it two weeks ago. But I’m sure there’ll be more opportunities to test it out.

    July 8, 2014 at 9:46 am
  2. Игорь Снежко

    For the client to work with its default settings the following ports need to be open:

    SIP Port UDP: 5091
    RTP Ports UDP: Range 11000 – 11015

    This are inbound or oundbound ports (connections)?

    July 8, 2014 at 10:20 am
  3. Andrew Kent-Brown

    Sometimes my remote extension (despite being provisioned as a remote extension) doesn’t ring when a call comes in. Right now I can call it form my mobile fine, but if I run the checker it passes the first test then fails the CB test.

    Looking at the system, the CB extension always seems to be connected to voicemail, like it tried to call back too quickly and the calling extension was in use at the time of course??

    July 8, 2014 at 11:07 am