≡ DMZ
What the hell is this!? The only demiliterized zone I’ve ever heard of involved the Korean war…
In router terms, a device configured within the DMZ is outside of any firewalls or other filters. It allows for unobstructed communication between the device and the Internet.
Why would you want to do this?
With VoIP, there are several reasons you might place a device in your router’s DMZ. If you are running a server of some sort, you may need to access it on several ports from the Internet. Without telling your router to send a request at this port to your machine, it will never get through. I won’t get too much into DMZ with servers, because anyone running one already knows this information…
With ATA’s (analog telephone adapters), such as one you might use with a VoIP provider like SunRocket or ViaTalk, DMZ is often used to improve call clarity.
How does this work?
In broad terms, SIP and RTP traffic leave your provider’s server and are sent first to your ISP’s modem. Then, it hits your router. Since most routers have firewalls blocking ports (such as those used with SIP and RTP), in some cases these packets NEVER reach your ATA. DMZ essentially opens a hole in your firewall and directs SIP and RTP traffic to your ATA.
Open my firewall? That sounds scary…
Well, yes and no. If you have a server, you’ll obviously want to setup a local firewall to protect important files. With an ATA, any security risks are minimal.
In order for anyone to actually do anything with your ATA from the Internet, you would have to enable remote administration. So, if you use DMZ, its recommended you leave remote admin off - but if you have to have it, use some obscure port no one will ever think of.
So how do I do this?
What am I psychic? Go to either http://portforward.com or Google your router’s make and model and the word DMZ. IE: linksys wrt54g dmz
Post any questions or problems you may be having with DMZ.
