Something

[priorities]
preroute=100
route=150
[$once]
[$init]
[contexts]
.*=default
[default]
^99991001$=tone/dial
^99991002$=tone/busy
^99991003$=tone/ring
^99991004$=tone/specdial
^99991005$=tone/congestion
^99991006$=tone/outoforder
^99991007$=tone/milliwatt
${username}^$=call check_addr_auth
${username}.=;caller=${username}
^......$=sip/sip:\0@192.168.9.12
[check_addr_auth]
${address}^192\.168\.9\.12:=return
.*=-;error=noauth