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I'm an ISP, and mails from our customers, using authenticated connections from another ISP, are hitting RCVD_IN_DYNABLOCK.

This problem (involving SMTP Auth connections from dynamic addresses) is similar to other "false positives" such as SPF_FAIL RCVD_IN_SORBS_DUL and various other RBL problems.

Note: The problem described was fixed in version 3.0.2. However, some MTAs such as Postfix don't support RFC 3848 and will therefore still exhibit the described problem (which you won't be able to correct by looking for authentication tokens since there aren't any, at least in Postfix).

*Update (2006-07-14): Postfix 2.3 includes support* for adding its own style of authentication info to its received headers by setting 'smtpd_sasl_authenticated_header yes' which is disabled by default. *SpamAssassin 3.1.4* and later includes support for this Postfix auth info. Also see \[http://blog.madduck.net/geek/2006.06.30-postfix-auth-anonymisation this blog post\].

Postfix Quickfix: Get latest versions of Postfix (at least 2.3.0) and SpamAssassin (at least 3.1.4) Add smtpd_sasl_authenticated_header = yes to the Postfix config. With that set, SpamAssassin should catch such authenticated emails as ALL_TRUST, bypassing possible SPF and RBL problems.

This is another Dynablock-related issue. If:

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