Asterisk over VPN over DSL / Cable

Now that the basic problems are solved with our new PBX (thanks to you folks), I need to turn my attention to how best to connect my partners up to the system.

My partners and I live at the points of a triangle approximately 40 miles on a side. Two of us have DSL connections to the Internet, one Verizon and one (myself) through a private ISP. Our other partner has a Comcast cable modem connection.

None of us are able to get static IPs, period. And, each of us is stuck with the DSL modem or cable modem that’s provided by our service providers, and each of those modems provides its own DHCP server to an internal, private-IP (192.168.x.x) LAN.

At the moment, our PBX (a Linux box running Fedora Core 5) is here in my office behind my DSL modem, on my private LAN. It connects to my partners by auto-forwarding their calls to their cell phones. But, eventually, and hopefully before too very much longer, it will be transferred to the co-location room at my ISP, where it will be on a multi-megabyte backbone, with a static IP number.

I would like to be able to set up IP (presumably SIP) phones (one or more) at each partner’s location and connect to the central PBX via the Internet. But, I’m REALLY unclear on how to do that when each of us is stuck behind a dynamic-IP DSL or cable modem which serves up a private-IP (192.168.x.x) LAN. Remember that we can’t get static IP numbers from our ISPs so that all we’d need to do is port-forward to a statically-numbered host on our LANs … no, that would be entirely too easy. :frowning:

Can it be done, or am I out of luck? If it can be done, can you all direct me to some reading material that will show me how?

This should be do-able.

BTW, I don’t have a Static IP, and I have Cox Cable. I have noticed that even though I am not guaranteed a static IP, as long as I don’t replace my router or tell my router to renew its IP, my IP is “static”.
However, as you are going to get your server in a colo with a static IP, this is kinda moot.

You don’t need static IPs for the phones, just the server. I currently do this with a softphone on my laptop. I can boot up my laptop and when the softphone boots up, contacts my server and logs in. At this point, it’s essentially the same as if I was on the lan (except for the speed of course).

It’s easier with IAX than with SIP, but it will work with both. Here is the setup instructions for IAX: … c141188987

Here’s a discussion on getting it to work with SIP: … 58255.html

It’s easier with IAX than with SIP

I suspected that it might be.

I see that Digium has what they call an IAXy module that converts a standard analog phone into an IP phone.

Could this be as simple as just installing the Asterisk server in my ISP’s colo room, then installing analog phones and IAXy modules at my house and each of my partners’ houses?

Sure, here’s a description of how to do just that:

short version:

You can use any SIP phones. Grandstream phones are cheap plastic toys, keep this in mind when you are trying to save money. AAstra and SNOM phones kick ass.

set qualify=yes, nat=yes, canreinvite=no, and host=dynamic in each phones sip.conf entry.

On the phones, turn on STUN support. and are two free STUN servers.

If you can, give the phones static LAN ip’s and forward port 5060 to them. Bonus- figure out what port(s) they use for RTP and forward those too.

set the phones to register/call to the server’s static ip.