[Asterisk-video] * 1.2, H.263, Grandstream GXV-3000 and no video

[Ruslan Valiyev]

Hello all.

I have subscribed to this list to ask you, people, about help 'cause  
I'm going crazy.

I have an Asterisk server (1.2) running Linux, also working as a  
router/firewall (iptables). It has external IP on eth0 and internal  
one on eth1.

I have two Grandstream GXV-3000 video SIP phones with H.263. One of  
the phones is directly connected to the Asterisk server. The other  
phone is in another country, that phone (as well as the local phone)  
is in NAT. Here's what it looks like:

Local phone (10.0.0.5)
     |
     |
Asterisk (82.82.82.82 and 10.0.0.1)
     |
Internet
     |
Remote router (83.83.83.83 and 10.0.0.1)
     |
     |
Remote phone (10.0.0.4)

iptables:
-A INPUT -p tcp -m tcp --dport 5060:5061 -j ACCEPT
-A INPUT -p udp -m udp --dport 5060:5061 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 5003:5005 -j ACCEPT
-A INPUT -p udp -m udp --dport 5003:5005 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 10000:20000 -j ACCEPT
-A INPUT -p udp -m udp --dport 10000:20000 -j ACCEPT

rtp.conf:
...
rtpstart=10000
rtpend=20000
...

sip.conf:
[general]
port=5060
bindaddr=0.0.0.0
canreinvite=no
tos=0x40
videosupport=yes
dtmfmode=rfc2833
defaultexpirey=1800
externip=82.82.82.82
localnet=10.0.0.0/255.255.255.0

[100];Local
type=friend
secret=try2hack
qualify=yes
nat=yes
host=dynamic
context=lyon

[200];Remote
type=friend
secret=try2hack
qualify=yes
nat=yes
host=dynamic
context=lyon

When making calls from both places, I get audio but no video. What am  
I doing wrong?

Thank you all very much in advance.