[asterisk-users] Asterisk rewrites "From" header when CALLERID(num-pres)=prohib_passed_screen is set

[effie mouzeli]

When the date was Thu Jan 19 2012 12:12:04, Stefan Schmidt wrote:

> Hello,
> 
> IMHO asterisk acts exactly as it should. How else do you think it should
> it prevent sending out the callerid name or num when you set it to prohib?
> 

This behaviour is new in 1.8, since in 1.6 it work differently (not forcing the "From" header to the default asterisk caller ID). Does the RFC say that a UAS must change the "From" header to secure privacy, even though there is a special header for privacy (or set privacy=full in Remote-Party-ID)? 

In case asterisk is not functioning as a PBX but as intermediate proxy, how do we secure its interoperability with other systems? So the issue here is that we are unable to change/keep the "From" header when CALLERID(num-pres)=prohib_passed_screen is set. 

> Asterisk doesnt support the privacy header for outgoing calls so
> changing the name and number is the only way to do this. Maybe you could
> do this in your dialplan with SipAddHeader("Privacy: full") instead of
> setting the prohib flag.

In http://tools.ietf.org/html/draft-ietf-sip-privacy-00:

6.2 UAS Behavior

   A UAS supporting this extension and receiving an INVITE from its
   trusted proxy looks for a Remote-Party-ID header field to identify
   the originator of the request. If the Remote-Party-ID contains an
   "rpi-screen" parameter with a value of "no", the UAS SHOULD NOT
   trust the validity of the information provided. Otherwise, the UAS
   SHOULD use the information provided to identify the caller rather
   than any information provided in the From header field.

So even if asterisk doesn't support the "Privacy" header, it supports the Remote-Party-ID header where the privacy=full parameter is present.


> in the Remote-Party-ID header is a special privacy option which asterisk
> sets when using this header so you will see the original values there
> but privacy is also set to full.


Kind Regards

-effie