README for qmail patches created by Gary Gendel

I started this project because I wanted to utilize the domain-based
blacklists from rfc-ignorant.org.  This required me to make patches to
qmail-smtpd.c.  The code changes is pretty minor, but some of the code had
to be shuffled to allow me to access some global variables that were declared
later than I needed them.  I've released this code into the public domain, no
restrictions.

The patches add the following checks:
1) Disallows '@', '%' and '!' in sender's name (Prevents relaying).  If any
   found it is logged (stderr) and rejected.

2) If NODNSCHECK environment variable is set then it skips the remainder
   of the checks. Otherwise:

3) It looks in controls/nodnscheck.  If the mail from domain is listed in the
   file then it skips the remainer of the checks.  For example, aol.com shows
   up in postmaster.rfc-ignorant.com and I actually get legitimate email
   from there.

4) It looks in controls/domainblacklist.  It does a domain blacklist lookup
   on the mail from domain for each blacklist server in the file.
   For example I list:

   whois.rfc-ignorant.com
   postmaster.rfc-ignorant.com
   
   If it is found on the list, it is logged (stderr) and rejected.

5) The mail from domain is queried for a DNS MX or A record. If none exists
   then it is logged (stderr) and rejected.

Installation:

Download the patch from http://www.genashor.com/qmail/ the patch will be named
qmailDomainChecks_xx.patch, where xx should be replaced by the
appropriate version number.

Go to the qmail-1.03 source directory and type:

   patch -p1 < [path-to-patch]/qmailDomainChecks_xx.patch

Compile and install as usual.  If it helps cut down your spam, I'd love to
hear from you.

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Any questions, comments email me: gary at genashor.com

Gary Gendel