Ask the Expert

I am using VoIP source code on Linux by Free Software Foundation and running into a few problems. Ca

Our VoIP code works fine, if we test it from a PC directly accessing the Internet using a dialup modem! But the same code doesn't work on a machine which is on LAN having Internet access through lease line. We have port restricted NAT. Even the register request gets Time Out! Our KEEP_ALIVE_PORT_TIME is 5 sec. Is that keeping VoIP working? We tried changing that time (0.5 sec to 5 sec), but the result was the same! Is there any special precaution to be taken why making the VoIP code run from LAN? Which are the timers or intervals I may need to change? I am using VoIP source code on Linux by Free Software Foundation. Can you help?

    Requires Free Membership to View

When running VoIP calls from the LAN and through a NAT to the Internet, you need to use some type of NAT traversal mechanism. It seems that you're trying to register and make SIP calls through your NAT to a SIP server on the Internet. If you have a port restricted cone NAT then the SIP Server with IP address X using port Y can only send a packet to your internal PC only if your PC sends a packet to SIP server with IP address X, port Y. If your SIP service provider has a STUN (Simple Traversal of UDP through NATs) server, you can implement a STUN client to help with NAT traversal through the port restricted cone NAT.
(http://sourceforge.net/projects/stun/)

This was first published in June 2004

There are Comments. Add yours.

 
TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to: