[dmarc-ietf] Re: ARC for internal use

[Richard Clayton <[e-mail]>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

In message <[e-mail]>, Alessandro
Vesely <[e-mail]> writes

>1)  Why does a large infrastructure need to authenticate its 
>Authentication-Results?  Cryptographic signatures are normally used to protect 
>against malicious tampering.  However, in many cases where the same ADMD adds 
>multiple ARC sets, they are all signed with the same key.  Sharing that key 
>allows any operator to alter data at will.  What threat are the signatures 
>intended to address?

"large infrastructures" are complex, have many different systems, some
of which are operated by third parties. Checking for consistency and for
unexpected changes allows for early detection of flaws

>2)  If the participating MTAs belong to the same ADMD, what benefit is expected 
>from having intermediate MTAs emit their own ARC sets?

early detection of flaws

>3)  According to Section 4.1.1. of RFC 8617, the AAR MUST contain the combined 
>authres-payload with all of the authentication results from within the 
>participating ADMD.  In some cases of multiple ARC sets, all AARs contain the 
>same data (including remote IP address).  In other cases, each MTA carries out 
>and reports its own checks as if it were a different ADMD, despite using the 
>same d=.  Which behavior is consistent with the specification?

I advise you not to care and for no-one else to bother to work out the
answer.

- -- 
richard @ highwayman . com                       "Nothing seems the same
                          Still you never see the change from day to day
                                And no-one notices the customs slip away"

-----BEGIN PGP SIGNATURE-----
Version: PGPsdk version 1.7.1

iQA/AwUBanB2ZGHfC/FfW545EQKx5wCdHjlK1ooOzO4n9xyLnD4PhEwIH2sAoIhZ
otlTM2p3m1cMXxESM2MitOTy
=0fVR
-----END PGP SIGNATURE-----