sip.conf

[general]
context=voiceservices           ; Default context for incoming calls
allowguest=no                  ; Allow or reject guest calls (default is yes)
allowoverlap=yes                 ; Disable overlap dialing support. (Default is yes)
tcpenable=yes                    ; Enable server for incoming TCP connections (default is no)
transport=udp
srvlookup=yes                   ; Enable DNS SRV lookups on outbound calls

disallow=all                   ; First disallow all codecs
allow=ulaw
allow=alaw
canreinvite=yes

dtmfmode=rfc2833
alwaysauthreject = yes  ;; change for SIP Proxy testing to 'no', otherwise 'yes'
promiscredir = yes              ; If yes, allows 302 or REDIR to non-local SIP address
videosupport=yes               ; Turn on support for SIP video. You need to turn this
maxcallbitrate=384
callevents=yes                  ; generate manager events when sip ua
localnet=192.168.1.0/255.255.255.0

realm=some.domain.com
externip=xxx.xxx.xxx.xxx
nat=yes
qualify=yes

[pmx2]
type=friend
user=pmx2
host=192.168.1.65
context=pstn-incomming