[asterisk-users] sip_chan - how to use value of the SIP 'To:' header field for extension logic

[Tomasz Zieleniewski]

Hi,

I have the following situation.
I have one account created in my VoIP provider.
Asterisk registers this account with the usage of
'register = ' command in the sip.conf file.
I have a number of aliases assigned to my user which
correspond to different public/PSTN numbers through which I am
accessible. When there is an incoming call from my sip provider
'some_extension' which corresponds to my registered user 'rings'.
this is because of such registration:
register => user:secret at myprovider.com/some_extension.
How can I now evaluate the value of the To header and perform
further routing logic.
What will happen if I don't specify the /extension value in the
register command?
Will it in such situation analyze the 'To' header to find matching extension??

I kindly ask for your help.
Cheers
Tomasz