Peer Details
Trunk Name: KoalaSip
disallow=all
allow=g729&gsm&alaw&ulaw
fromuser=<User-Sip Id>
host=203.122.248.173
nat=yes
port=5060
qualify=no
secret=<password>
type=friend
User Details
User Context: <User-Sip Id>
context=from-pstn
fromdomain=203.122.248.173
host=203.122.248.173
secret=<password>
type=user
username=<User-Sip Id>
Register String:
<User-Sip Id>:<password>@koalavoip.com.au
(Source Ref: Curtis of Koala) also refer here https://www.koalavoip.com.au/billing/node/75