Solved

Running VoIP in a NAT environment

Posted on 2004-08-19
2
2,026 Views
Last Modified: 2010-04-12
Hi,

We have three offices in different cities. Each office is connected with a T1 internet connection and the computers in the offices connect to the internet through a Linux server using NAT.

We want to install IP phone for each computer. So that the users in one office can talk to users in other offices as well as with them. We will be using IP phone sets from any company.

What I wanted to know, is it possible for users at one site, behind a NAT will be able to talk to users on other side of the NAT without VLAN?

Can we setup exchange or something for that using Linux server without using any hardware gateway or such?

And lastly, can our users get calls from any user on outside our networks who is using any net telephony service like net2phone or ICQ individually?

Thanks in advance.

Abhinay Sinha
0
Comment
Question by:abhinaysinha
[X]
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 Comments
 
LVL 15

Expert Comment

by:scampgb
ID: 11843751
Hi abhinaysinha,

You can do VoIP through routers that use NAT.  I've done this sucessfully before with no problems.

The "standard" for managing VoIP connections is called SIP - Session Initiation Protocol.  You can find out more from http://www.iptel.org

You can use either a SIP-compliant handset or a "softphone" on your PC.

X-Lite (http://www.xten.com/index.php?menu=products&smenu=xlite) is a very good SIP softphone.  

You will need to have a SIP server in order to manage the connections between the VoIP phones, or VoIP and the standard PSTN.
There are variety of organisations that will do this, some of them for free.  I personally use GossipTel (http://www.gossiptel.com)

Alternatively, you can set up your own SIP server on your network. A free one with lots of features is SIP Express Router (http://www.iptel.org/ser/)

As for free calls from outside users, this depends on who you're using for your SIP service.  Most of them will have peering arrangements with other SIP providers, so can route calls between them

I hope that this helps as a starter, let me know if you need any clarification.

0
 
LVL 2

Accepted Solution

by:
riparius earned 500 total points
ID: 11854255
You can also set up full PBX and conferencing with  Asterisk:   www.asterisk.org
It would use its IAX (Inter Asterisk eXchange) to work seamlessly between the Linux servers.  This also provides autoattendant, voicemail,...etc.  You would still need SIP softphones or SIP ethernet IP phones.

This would also allow a user in one city to grab an open telco line from another city and use it  if you add a POTS FXO card to each server.

Asterisk is an Open Source Linux  
0

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

In my office we had 10 Cisco 7940G IP phones that were useless as they were showing PROTOCOL APPLICATION INVALID when started. I searched through Google and worked for a week continuously on those phones, and finally got them working. This is a di…
I recently purchased a Bluetooth headset called the Music Jogger (model BSH10). The control buttons on it look like this: One of my goals is to use it as the microphone and speakers for Skype calls. In that respect, it works well. However, I …
Finding and deleting duplicate (picture) files can be a time consuming task. My wife and I, our three kids and their families all share one dilemma: Managing our pictures. Between desktops, laptops, phones, tablets, and cameras; over the last decade…

732 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