PUBLIC MARKS with tag qmail

This program will allow you to search and view messages in your qmail queue. It will also allow you to remove them, via expiration or deletion

Full Qmail Installation and Configuration Guide or Qmail Vmailmgr Tcpserver RBL SpamAssassin Relay-CTRL Qmail-Scanner Courier IMAP Guide POP3S SMTPS

Awstats is a commonly used program to calculate web statistics from your webserver logfiles. It can detect useragents, referers, unique visitors… But one of its another feature is to build usage reports from your mail server’s logfiles, as seen on this demo. Here is how to quickly configure Awstats to take profit of your Qmail log files…

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%.

I wrote the program "throttle.c," which you can insert into the tcpserver chain of commands for a qmail smtpd server. It takes one argument: the number of kilobytes per second to let through on the incoming file descriptor. Throttle does not throttle the outgoing file descriptor, because that's usually just status from your mail server. Additionally, throttle will set an alarm, so that any session longer than 15 minutes will expire and disconnect. This affords some amount of protection against lingering sessions that eat up your parallelism limit; I've seen such sessions from presumably trojaned DSL machines connecting to the mail server to send spam.

The original qmail-smtpd accepts by default all messages, checking later for the existence of recipients. So, if the message is delivered to not existing recipients, a lot of additional system work and network traffic are generated, with multiple expensive bouncing if the sender is a fake one. chkuser has been developed with the goal to improve the acceptance SMTP phase of qmail-smtpd. qmail-smtpd patched with chkuser may check the existence of e-mail recipients immediately in the SMTP acceptance phase of a message and rejects instantly all messages not directed to existing users, avoiding additional traffic, work and messages bounced more times.