Juha,

I host for example multiple domains for multiple users. This means that users rely on my services entirely to provide them with identity services. Ideally I would like to present the Certificate of domain X from user in domain X when I forward his calls through my proxy. Alternatively I could say I put certificate with CN=ag-projects.com in all request going outside my domains but then my white-label customers will become yellow.

So something to match business with the technicalities is required, don't you think?

Adrian

But then, the whole authorization thing would be nonsens.

Just imagine a host named "sip.badguy.com". This host has a valid certificate for its hostname. Then, this SIP proxy sends a SIP

request

with the header: From: "Klaus Darilion" <sip:klaus at darilion.com>

Now, what is the receiving proxy interested in? Does it want to

validate

the host or the sender (From header)?

there are other ietf means to validate the sender. usually they involve signing of from uri with the certificate of its domain. see for example

draft-rosenberg-sip-identity-privacy-00

for a good summary of the issues and problems involved. in proxy-to-proxy case, all that needs to be done is to validate the remote proxy.

IMO, I want to authenticate the sender in the From header. Thus, the certificate would have to match the SIP domain, and not the host name.

see above.

-- juha