General Firewall Settings

We strongly advise against connecting your IP PBX directly to the Internet without using a firewall. The probability of a ‘hack’ on an unsecured PBX is extremely high. Therefore always limit IP traffic from and to the telephone exchange on the basis of the necessary IP addresses. Please find the range of our IP telephony platform below.


This equals the following ranges:

  • until
  • until

Always use the range as indicated above, not only the IP addresses of individual servers. IP addresses may change or new IP addresses may be put into use.

Our telephony platform also features highly sophisticated fraud detection. This will quickly detect a hack at a switchboard and close the trunk for outbound traffic. However, this extra safety net is not a substitute for properly securing an IP PBX. When you use our Hosted PBX behind a router, generally no additional firewall settings are required.

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