[back-trunk]
type            =  friend
username        =  8880006111
secret          =  xxxx
host            =  x.x.x.x
dtmfmode        =  rfc2833
nat             =  no
canreinvite     =  no
insecure        =  port,invite
qualify         =  no
disallow        =  all
allow           =  ulaw
allow           =  alaw
allow           =  g729
context         =  shared-back-trunk-incoming

[back-trunk-ulaw]
type            =  peer
username        =  8880006113
secret          =  xxx
host            =  x.x.x.x
dtmfmode        =  rfc2833
nat             =  no
canreinvite     =  no
insecure        =  port,invite
qualify         =  no
disallow        =  all
allow           =  ulaw
context         =  shared-back-trunk-ulaw-incoming


Aug 10 12:17:15 DEBUG[21756]: chan_sip.c:7242 check_user_full: Setting NAT on RTP to 0
Aug 10 12:17:15 DEBUG[21756]: chan_sip.c:10497 handle_request_invite: Checking SIP call limits for device 8880006113
Aug 10 12:17:15 DEBUG[21756]: chan_sip.c:1401 __sip_ack: Stopping retransmission on '79119-3364165035-362070@203.220.50.5' of Response 1: Match Found