Re: [GnomeMeeting-list] NAT Problem over VPN

[Randall Smith <randall tnr cc>]

Damien Sandras wrote:
> Le dim, 04/07/2004 à 11:56 -0500, Randall Smith a écrit :
>
> [...]
>
>
> > 1. PC1 can ping PC3 and make TCP connections such as ssh.
> > 2. PC3 CANNOT connect to PC1 because I don't know how to alter the 
> > routing tables on Win2K and wouldn't be suprised if I couldn't.
>
>
> Then GM won't work. If PC3 can not connect to PC1, then PC3's GM won't
> be able to open the video and audio channels for transmission from PC3
> to PC1. Same for the H.245 channel which is not tunneled when using GM
> with NEtmeeting.
But PC3 can connect to PC2 (which is doing the masquarading).  This is 
the same principle of connecting through a router with NAT with PC2 
being the router.  If PC3 would send its UDP packets to PC2, PC2 could 
forward them to PC3 just like a router would.  But PC3 is trying to send 
the UDP packets directly to PC1.  How do I make it send them to PC2 
(@10.7.74.145).  I thought that's what the NAT setting was for, but it 
does not work.

> > PC1(GM) calls PC3(NM).  PC3 answers and the call is connected.  Video 
> > does NOT show on PC3 (I don't know about audio), but video option in 
> > toolbar ungrays.  No video or audio on PC1.  Ethreal shows that TCP 
> > traffic is OK and UDP from PC1 -> PC3 is OK, but UDP from PC3 -> PC1 is 
> > sent to 192.168.3.2 which PC3 CANNOT RESOLVE!  PC3 should send its UDP 
> > packets through 10.7.74.145, but it appears that that NAT option in GM 
> > is not working (probably b/c its not a public IP).  So how can I make 
>
>
> Indeed, NAT translation only works with private IPs, it doesn't make
> sense for private to private calls.
Do you mean only works with public IPs.  All of my ips are private.
> > this work.  Also, why does PC3 not show video from PC1 when I can see 
> > the UDP traffic arriving?
>
>
> If PC3 can not connect to PC1, I would be very suprised that the traffic
> arrives.
But PC1 can connect to PC3
route add -net 10.7.0.0 netmask 255.255.0.0 dev ppp0
I can see the UDP packets using ethereal and tcpdump.  That's why video 
WORKS from PC1 -> PC4 even though PC4 has the same network setup as PC3. 
 That's why I included PC4, to show that the UDP packets are traversing 
the VPN and there is something specifically wrong with the NetMeeting setup.

Randall
> > PC1 calls PC4.  PC4 answers.  PC4 shows video.  PC4 has no video or 
> > sound card (just used to test) and sends no udp packets out.
> >
> > If you can figure this out and you live in New Orleans, I'll buy you 
> > lunch :)
>
>
>
>
> > Randall
> >
> >
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