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GNU Gatekeeper FAQ

1. What is a H.323 gatekeeper ?
1.1. Tell me more about H.323, OpenH323 and gatekeepers.
1.2. Can I use the GNU Gatekeeper for NAT/masquerading H323 calls through a firewall ?
2. Why should I use a gatekeeper ?
3. What OS do I need to compile / run the gatekeeper ?
4. Can I help in the development ?
5. What additional features are planned ?
6. What implications does the GPL license have ?
7. How do I get support

1. What is a H.323 gatekeeper ?

A H.323 gatekeeper controls all H.323 clients (endpoints like MS Netmeeting) in his zone. Its most important function is address translation between symbolic alias addresses and IP addresses. This way you can call "jan" instead of knowing which IP address he currently works on. See also the Wikipedia entry about GnuGk.

1.1. Tell me more about H.323, OpenH323 and gatekeepers.

In brief; H.323 is a communications standard for audio, video, and data over the Internet.
See also Paul Jones' primer on H.323 or the free IP Telephony Cookbook.

1.2. Can I use the GNU Gatekeeper for NAT/masquerading H323 calls through a firewall ?

Yes, you can use GnuGks proxy function to tunnel calls through NATed networks or firewalls.

2. Why should I use a gatekeeper ?

If you currently use a client and are happy with the way it works there may be no reason to use a gatekeeper. If you however work in a larger VoIP setup using symbolic addresses is definitely a great plus. More importantly the gatekeeper is the key to the management of a VoIP network.

VoIP gateways for example register at the gatekeeper and the gatekeeper finds the right one for you to use to call a specific number.

A gatekeeper can also manage the bandwidth used by the clients. Currently we grant all bandwidth requests until a predefined limit is reached. In the future we could implement a more detailed schema.

3. What OS do I need to compile / run the gatekeeper ?

Stable version of the gatekeeper run on all platforms supported by the OpenH323 / H323Plus library, which include a wide variety of Unixes and MS-Windows and MacOS X.

4. Can I help in the development ?

Sure, this is an Open Source project! Even if you are not a programmer we always need people for testing newly implemented features.

If you are a programmer, go ahead and fix things you find are broken or missing. I suggest that you contact me before you start, so I can provide you with the most current development version. I also try to coordinate the various people who are working on the gatekeeper to get you somebody to discuss your problems with and avoid duplication of work. If you send in patches, I prefer a "diff -u".

5. What additional features are planned ?

There is no fixed roadmap but we have a number of ideas for new gatekeeper features. Please contact us if you need additional features.

6. What implications does the GPL license have ?

The gatekeeper is not published under the same license as OpenH323 / H323Plus. While OpenH323 / H323Plus uses the MPL (Mozilla Public License), the gatekeeper is published under GPL (GNU Public License).

The GPL requires that all derived works must be published under GPL also. That means that you must publish full source for all extensions to the gatekeeper and for all programs you include the gatekeeper into.

If that's not what you want, you must interface to the gatekeeper through the status thread and communicate via TCP with it. That way you only have to integrate the basic functionality into the gatekeeper (and provide source for that) and can keep other parts of your application private.

7. How do I get support

You can send your questions to the Gatekeeper Users mailinglist (Subscribe) for free support.

Or you can get a commercial support contract for the GNU Gatekeeper.



Last updated: 22. Mai 2011
Page maintained by Jan Willamowius