[root@server1 asterisk]# cat sip.conf
 [general]
 context=default
 disallow=all
 port=5060

 maxexpirey=3600
 defaultexpirey=120
 register => 214103:102@sip.xxxx.com/214103
 language=en
 nat=yes
 canreinvite=no

 diallow=all
 allow=ulaw
 allow=alaw

 dtmfmode=rfc2833

 [214103]
 type=friend
 secret=102
 username=214103
 fromuser=214103
 fromdomain=sip.xxxx.con
 host=server.pol.net.in
 nat=yes
 canreinvite=no

 [123458008];X-lite client 20
 secret=102
 type=friend
 host=dynamic
 context=internal

 [123458009];-lite client 21
 secret=102
 type=friend
 host=dynamic
 context=internal


 [123458007];-lite client 21
 secret=102
 type=friend
 host=dynamic
 context=internal


 [215104];-lite client 21
 secret=102
 type=friend
 host=dynamic
 context=internal


[general]
static=yes
writeprotect=no


[internal]
exten => 214103,1,Dial(SIP/216105)