Some other examples of using check_* in sendmail 8.8

This is a short list (in no particular order) of some other examples how to use the check_* rules in sendmail 8.8:

• Anti-Spam Provisions in Sendmail 8.8
• Alex Petrov wrote rules to check arbitrary network blocks in CIDR notation.
• Andy Harper wrote a very complete and highly configurable set of check_ rulesets.
• Another proposal checks for an empty Message-Id:
• Jim Bacon sent me a version of check_rcpt which uses a patch from Miquel van Smoorenburg to find out for which machines your mailserver is secondary MX and therefore should allow relaying. This avoids maintaining just another file (RelayTo).
• Alexander Zangerl proposes some extensions.
• Thom Henderson suggests this version.
• Domain-wide mail relay limitation by Steve VanDevender
• Gregory Neil Shapiro has posted these examples.
• Kenneth Herron made another interesting proposal.
• Tom Smith proposed some extensions to check_mail.
• A .mc file from Wolfgang Rupprecht.
• Ted Deppner proposed an interesting extension for check_rcpt. It detects some wierd kind of spam!
• William Mee suggested some check_* rulesets which can perform many checks.
• Ted Roberts suggested to use a map lookup instead of a plain text file (e.g., a class) to list spammers.
• The Sendmail Antispam Measures on acpub.duke.edu also make use of maps in all possible locations.
• Posting with explanations for patches for filtering on email src/dest IP addresses - anti-relay patches
• Another checkcompat() function which has a ``backdoor''.
• Making sure your site does not relay spam e-mail (has a good explanation how these rules work).
• Protecting internal aliases against E-Mail from external addresses.