SIP Trunk Security 3

[exsmogger]

Hi all,

Many of you saw the thread I started on SIP trunk ghost calls. I had intended to build a firewall from a Raspberry Pi and place it in front of my BCM50, but the project turned out to be more complex than I thought in trying to program iptables firewall software. Since my project involved adding a second Ethernet port to the Pi I had to create a network bridge which seriously changed the way packets flow through the firewall. It sort of worked, but not nearly good enough. I shelved that idea for the time being and came up with another solution that has shielded my BCM50 from the SIP scanners, but also allows my SIP trunks to work behind NAT without having to use port forwarding. Attached is a Word document I wrote that details the process I went through.

Brian Cox
Georgia Telephone

http://Georgia-Telephone.com

http://www.linkedin.com/in/briancox1952

 

[curlycord]

Nice, have a star.

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Add me to LinkedIN

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http://www.curlycord.com

Toronto, CAN

 

[Firebird Scrambler]

And another one from me.

Firebird Scrambler

Nortel & Avaya Meridian 1 / Succession & BCM / Norstar Programmer

Website =

http://somertel.com

linkedin

 

[exsmogger]

Thanks gents. This is a work in progress as the script kiddies are always looking for new methods in their quest for "free" phone calls. I believe the SIP providers need to take more responsibility for security than they do currently. I absolutely cringe at all the articles on SIP that advise people to forward port 5060 to their phone system.

Brian Cox
Georgia Telephone

http://Georgia-Telephone.com

http://www.linkedin.com/in/briancox1952

 

[koulioumbis]

Super! a star too.

 

[exsmogger]

I appreciate that. All is still quiet on my BCM50 since I figured out how to keep my system behind NAT and at the same time allow real calls to come through. I haven't had even one SIP scanner hit my system in almost 2 weeks. The firewall is doing its job.

Brian Cox
Georgia Telephone

http://Georgia-Telephone.com

http://www.linkedin.com/in/briancox1952