[Asterisk-Users] prevent callerid spoofing between asterisks

[elkur]

Hi all

For example here is asterisk-A sip.conf:
[123456]
type=friend
secret=xxyyzz
nat=1
qualify=100
host=dynamic
canreinvite=no
callerid="" <123456>
context=sipphone
dtmfmode=rfc2833

Sip-phone can make and receive calls and callerid 
value overrides phones config here, thats nice.

OK, lets set up an Asterisk-B as sip peer and also send all our
outgoing traffic to Asterisk-A, useing same the sip account.

#Asterisk-B sip.conf:
register => 123456:xxyyzz at ip.adr.of.asteriskA
[asteriskA]
type=friend
username=123456
secret=xxyyzz
host=ip.adr.of.asteriskA

#Asterisk-B extensions.conf:
exten => _XXX.,1,Dial(SIP/asteriskA/${EXTEN})


Now if I make a call from asterisk-B to asterisk-A, I'm able 
to spoof callerid, because in this case asterisk-A doesn't 
override callerid. How to prevent that?

Thanks.
Elkur