I've posted it here. I've been testing it with 2.1.6-alpha http://www.sysdesign.ca/archive/mod_dnsbl_lookup-0.90.tar.gz
The README file should describe everything. This is a module providing an optional utility function intended for (but not limited to) mod_smtpd. The function allows the user to query DNS based blocklist databases, both DNSBL and RHSBL style, for arbitrary data. This can be used for all kinds of filtering and anti-spam use, including score systems such as spamassassin. In the case of SMTP the query can be the client's IP, client's host name, and the domain used in the sender's address. I know that Rian is currently redesigning much of mod_smtpd but for demonstration purposes I have included code that brings spam blacklisting functionality to mod_smtpd 0.1. If a blacklisted client connects, they will be denied service. It is more standard however to have these checks done after RCPT TO, at which time the envelope domain can also be checked against RHSBL. It would be great to hear some feedback as I am very new to writing these modules. I've tried to use the proper apr_ calls whenever available.
