PUBLIC MARKS from camel with tags qmail & spam

MAGIC-SMTPD is a drop in replacement for Dan Bernsteins qmail-smtpd, and was originally designed to be part of the LinuxMagic Magic Mail Server. This OpenSource version has been released to allow others to benefit from it's anti-spam components, and valid user checking to reduce server loads and spam volumes. It is designed to support stock qmail installations, qmail/vpopmail installations, as well as having database support. Designed for ISP service, this will work for all mail servers large and small. Comments are welcome. Support for other mailers is expected in the future. Complete support packages are also available.

smtp-delay is an add-on/plug-in intended for use with qmail. It was written primarily to add banner delays and antipipelining to qmail. These two features are known to be able to block certain types of spam and virus mail sent through non-rfc-compliant SMTP engines. When I looked around for programs to add this functionality to qmail, I found only one such program, and didn't like the way it was done. BTW...I have the same objections to the way its done in sendmail 8.13.x. Since banner delays (the server pausing for some time before issuing an SMTP banner) cause every SMTP connection to take longer, I thought it would be a good idea to somehow exempt "legitimate" mail servers...or at least not subject them to long banner delays. So I decided to tune the banner delay time based on the connecting IP's reverse DNS. IPs with no rDNS get treated the worst (longest banner delay). IPs with rDNS matching a regex intended to detect dynamic/end-user IPs get a moderate delay. All other IPs get a very short banner delay...just long enough to see if they immediately pipeline (send SMTP commands before the banner's been sent). The original intent for smtp-delay was that it should be run before rblsmtpd, and simply set the RBLSMTPD environment variable if applicable, letting rblsmtpd issue the 4xx response. Pretty early on, I realized smtp-delay should be able to run standalone (without dependence on rblsmtpd to do its talking) and issue a 4xx response on its own. Lately, the spam load against our mail cluster has gotten so bad that I've started running smtp-delay after rblsmtpd, based on the idea that there's no point waiting out a long banner delay holding an open socket to an IP we have no intention of accepting mail from anyway. This reduced our concurrency by about 20%.

is an unidirectional Mail Filter and Virus Scanner for Qmail. qmvc works in conjunction with the "dot-qmail" mechanism for qmail-local. It is entirely designed for Qmail and there are no additional patches required for Qmail.

Greylisting is an interesting method to fight against spam. It's based on the fact most spam is not sent out by fully compliant MTA's. How it works and how this can be implemented into Qmail?

Filtering add-ons to specific mail server applications and instructions on how to filter spam with specific servers. Remember that spam filters are also available that work with any mail server on a particular operating system, and that some spam filters can be found that function on any operating system, with any mail server.

This HOWTO should give an overview on using spamdyke SMTP filter in front of the mail-mta/netqmail mailserver. From the spamdyke website: spamdyke is a filter for monitoring and intercepting SMTP connections between a remote host and a qmail server. When a connection is established from a spam source (as determined by the active filters), spamdyke will reject the email -- qmail never sees it.

spamdyke is a filter for monitoring and intercepting SMTP connections between a remote host and a qmail server. Spam is blocked while the remote server (spammer) is still connected; no additional processing or storage is needed.