How to make a sip phone register properly behind a Checkpoint Firewall

Posted on 2014-07-21
Last Modified: 2014-11-14
When the SIP phone that resides behind the checkpoint firewall tries to register with the SIP Proxy on the internet, the checkpoint firewall will use the IP from the firewall as the registering IP for the phone. The registering IP needs to be the IP of the internal IP address of the phone or the SIP proxy will not know how to reach the phone to direct a call to it.
Question by:MorganGunter
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
LVL 15

Expert Comment

ID: 40212020
No, If you use the Private IP address behind the Firewall as your registration IP, there is not routing capability.  

Your Firewall and you IPBX need to be SIP / NAT aware, and I don't know the settings for your Checkpoint.  


Accepted Solution

MorganGunter earned 0 total points
ID: 40225055
Found a solution to the problem. By adding a local SIP Proxy that communicates with the main external proxy the phones will register with the internal proxy first that sits behinds the customer firewall. The Local DNS server will direct the sip registration to the internal proxy so the phones will properly get register with the main VOIP PBX.

Author Closing Comment

ID: 40442245
Found my own solution as the firewall would not allowed the phones to register.

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I'm Dumb-phoned(ed) Last week, I noticed this message when adding events to my Google Calendar: On June 27th (2015), Google is removing SMS as a notification option for Google Calendar events.  Their assumption is that enough people have smart p…
Transferring data across the virtual world became simpler but protecting it is becoming a real security challenge.  How to approach cyber security  in today's business world!
Internet Business Fax to Email Made Easy - With eFax Corporate (, you'll receive a dedicated online fax number, which is used the same way as a typical analog fax number. You'll receive secure faxes in your email, fr…
Sending a Secure fax is easy with eFax Corporate ( First, Just open a new email message.  In the To field, type your recipient's fax number You can even send a secure international fax — just include t…

705 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question