Re: [GnomeMeeting-list] Video loss when connecting via 2 Linksys routers

[Damien Sandras <dsandras seconix com>]

Le mar 29/04/2003 à 14:40, Kenneth R. van Wyk a écrit :

> I am forwarding all of the above to my desktop system.  (I would be happy
> to send the entire list of open ports, if that would help.)  The router
> uses NAT, and I do not have IP translation turned on within GnomeMeeting. 
> Also, I have already disabled H245 tunneling and fast start, since I
> frequently need to talk with MS-Netmeeting systems.
> 

Do not forward the ports, perhaps it puzzles the NAT implementation of
the linksys router. Only forward 1720, for incoming calls.


> Hmmm, I did a bit more investigating...  The router/firewall at both ends
> of the connection is a Linksys BEFSR41 with the latest firmware from
> linksys.com.  All of the info that I've found on the Linksys site in their
> "knowledge base" recommends setting the netmeeting host as a "DMZ" host,
> but that would entail allowing *all* incoming traffic to those systems. 
> As a security professional, that's something that I'd really prefer
> avoiding...

I understand, but Netmeeting doesn't support fixed range of ports,
GnomeMeeting does, and GnomeMeeting can also do IP translation as a
'workaround' to firewall problems with Netmeeting.

You have 2 solutions here as you are using GM:
- use port forwarding together with IP translation as if the modem was
not natively able to do H.323 and NAT.
- not using port forwarding and not using IP translation, but only
forward TCP 1720

A mix of both (the current situation) is not a good idea. The fact that
NM works tends to prove that your router supports H.323; so I would try
the second solution if I was you.

> 
> However, I did a bit of additional googling and found the following link:
> http://www.compusmart.ab.ca/mikes/lvideo7.html#linksys
> It talks about using the Linksys UPnP (Universal Plug-n-Play) feature to
> forward MSN traffic to a designated host.  I will investigate doing the
> same for netmeeting this evening when I am at home again.
> 

Linux doesn't support yet (to my knowledge) UPnP.

> Any other Linksys users out on this list?  What port forwarding settings
> are you using?
> 
> Cheers,
> 
> Ken van Wyk
> 
> 
> 
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 _	Damien Sandras
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