PUBLIC MARKS with tags qmail & mail

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.

To test and benchmark several common SMTP servers for Unix. This is inspired by the work done by Matthias Andree at his Postfix vs. qmail - Performance page. His information, while likely still highly relevant is based heavily around file system I/O and not overall performance of the MTA. Additionally, more MTAs and OSs will eventually be tested here.

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.

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.

qconfirm is an implementation of a delivery confirmation process for a mailing list or mail address. It is invoked by qmail-local through a dot-qmail file, and can reduce the amount of junk mail hitting a mailbox or the mailboxes of mailing list subscribers. qconfirm performs this delivery confirmation process either sender based or message based. When used for a public mail address, not a mailing list, qconfirm is capable of detecting follow-ups on mail messages originated from this mail address, and doesn't request delivery confirmation is this case. qconfirm also is able to identify delivery confirmation requests from recipients of mail messages, and automatically confirms the delivery if desired.

Ce plugin pour Qmail implémente une vérification de l'adresse du destinataire et du tarpitting. Tarpitting : Cela consiste à attendre un certain temps avant de prendre en compte une nouvelle commande smtp. En cas de gros flood à coût de RCPT TO multiples cela permet de ralentir le floodeur tout en préservant les ressources du serveur. Dans ce module le tarpitting est utilisé de deux façons : * Si la commande RCPT TO correspond a un utilisateur qui n' existe pas. * Si il y a plus de START_TARPITTING commande RCPT TO dans une session. Vérification du destinataire : Par défaut, Qmail ne vérifie pas au niveau smtp si le destinataire final existe, il le fait au moment de délivrer les mails. Cela implique que même si le destinataire n' existe pas le serveur va prendre en charge le mail. Le fait de vérifier l' existence du compte au niveau smtp va permettre trois choses : * Economiser des ressources serveur, car le mail n' est pas traité par la machine. * Gagner de la bande passante, pour les mêmes raisons. * Alléger la queue, puisque vous n' acceptez plus les mails qui ont de faux destinataires, Qmail n' envoie plus de bounce vers l'expéditeur pour l' informer que son mail n' a pu être délivré. De plus si l' on considère que la grande majorité des spams/virus ont de faux expéditeurs, ça vous évite de prendre le bounce du bounce. Fonctionnement : Rcptchecks va tester l'existence du destinataire dans une base de données MySQL. Si le client smtp le droit de relayer, autrement dit si la variable d' environnement RELAYCLIENT existe les tests n' auront pas lieu.

Osez Qmail

What we'd like to do is allow mail relaying from a selected group of IP addresses only. If you've just been reading the qmail newbie's guide to relaying, you know that we do this be setting the environment variable RELAYCLIENT in qmail-smtpd's environment

Web-based email system, Web-based administration tools