How to configure VoIP through firewall

Unanswered Question
Nov 24th, 2009


We have a VoIP solution that is currently directly connection from the ISP router into our network. I need guidance on how to configure VoIP to traverse a firewall.

We have a secure redundant solution for the data connection, but I have no idea when it comes to VoIP as to which ports and protocols to allow/ block with achieving optimum security.

  • This is a Hosted Voice Solution with Call Manager at the ISP.
  • There is a PA-2FE-TX card that provides the VoIP from the router.
  • The router provides DHCP for the Phones only.
  • There is an internal windows DHCP for the PCs.
  • Data and VoIP provided by same ISP.

Attached are diagrams of a) current set-up and b) what I’m aiming for.

Any help is appreciated. Thank you.

I have this problem too.
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KonradStepniewski Tue, 11/24/2009 - 03:39

Your phones use SCCP or SIP protocol to communicate with CM + TFTP for config and firmware, you need to open RTP stream to phones - not sure where is your voice GW. Probably you will need HTTP/HTTPS or someting more like LDAP or Cisco Directory.

More less that's all but best option is to check with ISP what need to be open exactly.

rate if this help


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