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Email filtering, spam, and other random notes on SMTP.

Monday, 30 May 2005 20:47
It is amazing to me how complex SMTP can be at times. Simple mail gets complicated due to the unending arms race between the spammers and the users.

Email hates you and wants you to be unhappy. Compatibility is favored over elegance.

Mail server prerequisites

Make sure that the IP of your server resolves back to your domain name. If you don't then most mail servers will flag your mail as spam. This is something I always forget when setting up a new server...
So you should be able to do an nslookup yourname.com and get an IP, then take that IP and do an nslookup IP. You should get your name back.

SPF - Sender Policy Framework

SPF: Introduction
The SPF Setup Wizard - helps you build SPF txt records.

Qmail

Lately I setup a Qmail server using CentOS: I used the following directions and I was very pleased. (btw: qmail-showctl is a nice program to view settings for qmail.)
qmail: Second most popular MTA on the Internet
POP-Toaster using Qmail, Vmailmgr, Courier, and Squirrelmail
VMailMgr
QMRTG - a qmail activity analyzer
Chris Hardie - qmail Anti-Spam HOWTO
SourceForge.net: qmHandle - a tool for the qmail queue
DomainKeys with qmail Howto
qmail SPF (Sender Policy Framework) patch


Exim

Linux + GNU = Humans Enabled: Easy 'mail by smarthost' SMTP server in Ubuntu 12.04 GNU/Linux - dpkg-reconfigure exim4-config


Postfix

Virtual Users And Domains With Postfix, Courier And MySQL (Fedora 8) | HowtoForge - Linux Howtos and Tutorials
OpenSourceHowTo.org - MySQL users, PostfixAdmin, Postfix, Dovecot & SquirrelMail with userprefs stored in mySQL
Johnny Chadda .se : Mail server HOWTO - Postfix and Dovecot with MySQL and TLS/SSL, Postgrey and DSPAM
Howto:Postfix - Fedora Directory Server
Postfix Wiki
Postfix Backscatter Howto
Postfix Admin - Web based administration interface
Postfix MySQL Howto
Labcoding » Blog Archive » Installing a Postfix mailserver on CentOS 5


SPAM filtering

SPAM. SPAM. SPAM. Why do you fill my inbox so? Emails without valuable payload. The words have no meaning for you or me. Only to serve as an annoyance for the economical gain of another. The spammers are an intelligent bunch. They know about filtering too. So there is a constant game of cat and mouse. One day it will all go away and I will think of you no more.
About Us | Project Honey Pot


Challenge-response and Email passwords

Tagged Message Delivery Agent (TMDA) Homepage
Proper principles for Challenge/Response anti-spam systems
taint.org: Justin Masonâ??s Weblog » An anti-challenge-response Xmas linkfest

Mail filtering (tagging/proc stuff)

Here are four very good articles on mail filtering by Brian Hatch on SecurityFocus.
Filtering E-Mail with Postfix and Procmail, Part One
Filtering E-Mail with Postfix and Procmail, Part Two
Filtering E-Mail with Postfix and Procmail, Part Three 
Filtering E-Mail with Postfix and Procmail, Part Four


Another good looking project is DSPAM
Active Spam Killer
Check Google E-Mail (Gmail) from an RSS Feed - Tech-Recipes.com

DomainKeys

DomainKeys - Wikipedia, the free encyclopedia
DomainKey Policy Record Tester
Setting up DomainKeys on Centos | Josh's Blog
Mail relay testing
Spam Resource: Backscatter: What is it? How do I stop it?
Backscatterer.org - backscatter ip tester
SPF: Implementations
SPF: Project Overview
Email Help, Backscatter, and How to Stop Spam Spoofing with SPF â?? 2Rrealms.com


graphing/analysis

Mailgraph Homepage - simple mail statistics RRDtool frontend for Postfix and Sendmail.
CodeProject: "C# Hooks For RRDtool".

Setting Up Email: A Postfix/Dovecot HOWTO - RimuHosting
Dovecot


Google hosted / gmail

Mark Lyon's GMail Loader (GML) - Import Your Mail into GMail
Ubuntu sendmail using smtp.gmail.com


cmdline mail stmp clients

mailsend - Send mail via SMTP protocol from command line - Google Project Hosting - open source written in ANSI c. MacOSX,Linux,Windows. examples - mailsend
Blat - Windows Command Line SMTP Mailer - Blat is a Windows (32 & 64 bit) command line utility that sends eMail using SMTP or post to usenet using NNTP. Small,Fast,Easy to use,RFC Compliant. sforge hosted Blat

Last Updated on Friday, 29 November 2013 14:00