M4 RPID/PAI
RPID headers defined in https://tools.ietf.org/id/draft-ietf-sip-privacy-04.txt:
Remote-Party-Id RPID-Privacy
PID headers defined in https://datatracker.ietf.org/doc/html/rfc3325:
P-Asserted-Identity Privacy
Forward RPID / Forward PAI
OP and TP have separate options: Forward RPID and Forward PAI in their settings.
The logic to pass these headers are in this order:
OP->TP
OP Forward RPID/PAI options tell if it is allowed to pass/forward RPID/PAI headers from OP to TPs.
If headers are passed from OP to TPs, then TP Forward RPID/PAI options tell if these headers should be passed to the TP.
If OP denies RPID/PAI header forward, then RPID/PAI headers coming from this OP will be dropped and TPs will not have any RPID/PAI headers to be forwarded.
In other words - OP makes a call that can pass over some TPs. If OP denies RPID/PAI forward, there is no difference what RPID/PAI settings are on any of the TPs for this call - these headers are already dropped by OP. Only when OP allows RPID/PAI header forward, then separate TPs RPID/PAI settings can have an impact on the result.
| OP setting | TP setting | Result |
|---|---|---|
| Forward RPID: yes | Forward RPID: yes | RPID headers are forwarded to TP |
| Forward RPID: yes | Forward RPID: no | RPID headers are NOT forwarded to TP |
| Forward RPID: no | Forward RPID: yes/no | RPID headers are NOT forwarded to TP |
Same logic applies to the PAI settings.
Change RPID/PAI Host
Change RPID/PAI Host option in the OP settings changes the IP address in the RPID/PAI headers to the Proxy server's IP address.
Example
Incoming headers:
Remote-Party-ID: <sip:390458446594@201.105.251.49>;privacy=off;screen=yes P-Asserted-Identity: <sip:390458446594@201.105.251.49;user=phone>
are changed to:
Remote-Party-ID: <sip:390458446594@116.203.110.224>;privacy=off;screen=yes P-Asserted-Identity: <sip:390458446594@116.203.110.224;user=phone>
Where 116.203.110.224 is the Proxy server's IP.
NOTE: if the host in the RPID/PAI header comes as a hostname, e.g some.server.com, then it will not be overwritten with the IP address.
Advanced modifications
Advanced modifications to RPID/PAI headers can be done using Transformations.
