Asterisk video call

I have allowed TCP and UDP ports 5060, 10000-11000.

root@voip:/etc/asterisk# lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux testing (stretch)
Release:	testing
Codename:	stretch
root@voip:/etc/asterisk# uname -a
Linux voip 4.2.0-1-amd64 #1 SMP Debian 4.2.5-1 (2015-10-27) x86_64 GNU/Linux
root@voip:/etc/asterisk# asterisk -V
Asterisk 13.6.0
root@voip:/etc/asterisk#

# ----------------------------------
# /etc/asterisk/extensions.conf
...

[pokus]
exten => 100,1,Dial(SIP/100,20)
exten => 100,2,Hangup

exten => 101,1,Dial(SIP/101,20)
exten => 101,2,Hangup

exten => 102,1,Dial(SIP/102,20)
exten => 102,2,Hangup

allow=h263
allow=h263p
allow=h264
allow=h261

# ----------------------------------
#/etc/asterisk/rtp.conf
...
[general]
rtpstart=10000
rtpend=11000
stunaddr=stun.ekiga.net:3478



# ----------------------------------
# /etc/asterisk/sip.conf
...
[general]
;preferred_codec_only=yes
;disallow=all
;allow=ulaw
;allow=ilbc
videosupport=yes

externhost=example.net
externip=1.2.3.4

[100]
type=friend
auth=md5
username=100
secret=dshfdhoadfnhfodjnsdoh
callerid=(Test user<100>)
host=dynamic
nat=yes
context=pokus
videosupport=yes
disallow=all
allow=ulaw
allow=h263
allow=gsm

[101]
type=friend
auth=md5
username=101
secret=dshfdhoadfnhfodjnsdoh
callerid=(Test user<101>)
host=dynamic
nat=yes
context=pokus
videosupport=yes
disallow=all
allow=ulaw
allow=h263
allow=gsm

[102]
type=friend
auth=md5
username=102
secret=dshfdhoadfnhfodjnsdoh
callerid=(Test user<102>)
host=dynamic
nat=yes
context=pokus
videosupport=yes
disallow=all
allow=ulaw
allow=h263
allow=gsm