Re: [GnomeMeeting-list] Major ILS change

On Mon, 15 Mar 2004 11:01:53 +0100
Damien Sandras <damien sandras it-optics com> wrote:


> That won't happen as long as at least one of the endpoints is using
> 1720. 

It is not a requirement for a H.323 call that one (or either) endpoint
be listening on port 1720. That port is simply a "well known" port that
all endpoints agree to use in the absence of any other information.
Using an ILS (or LDAP server) is an excellent example of where port 1720
is NOT required, because you can advertise that you are using another
port for incoming calls.

> But I don't understand what your approach brings as advantage to
> the current one. Perhaps I'm missing something in the explanation. It
> would however decrease the load of the server.

The approach I described allows you to deny registration to people who
cannot possibly receive calls (because they are behind a NAT firewall
which is not H.323 aware) while not forcing everyone to use port 1720
(which I suspect will cause many people to be rejected who are perfectly
able to receive calls).

Consider the situation where you have three people all on the same local
LAN behind the same NAT firewall. Forcing the use of port 1720 means
only one of them could be registered with the seconix ILS as only one of
them can receive incoming connections on port 1720. To my mind, this is
a serious restriction, especially as some ISPs use NAT firewalls.


 Craig Southeren, craigs postincrement com
 Post Increment - Software, Consulting and Services
 Co-founder of the only open source H.323 project
 Phone: +61 2 43654666   Fax: +61 2 43673140   Mobile: +61 417 231046
 ICQ: #86852844          MSN: craig_southeren hotmail com   
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