I have two asterisk boxes connected via SIP protocol. I want to deploy SIP peer authentication to this connection. What is the needed configuration? I have the following configuration but changing username and secret does not affect the connection at all!

sip.conf in box 68:

[general]
t38pt_udptl=yes,none,max
datagram=400

[p68]
host=192.168.0.68
type=peer
username=test
secret=testtest
context=from-trunk
qualify=yes
insecure=port,invite
canreinvite=no

sip.conf in box 67:

[general]
t38pt_udptl=yes,none,max
datagram=400

[p67]
host=192.168.0.67
type=peer
username=test
secret=testtest
context=from-trunk
qualify=yes
insecure=port,invite
canreinvite=no

Thanks in advance