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@@ -1 +1,123 @@ +# -*- mode: org -*- + Something like spamgourmet. + +* WHY THIS EXISTS +Having a public email address is an invitation to spam. Private email +addresses allow you to filter your spam based on how much you receive +and from whom it came. Instead of giving your main email address to +every web site you run across, you can give a private email address to +each web site (e.g., "facebook@myspam.example.com" for Facebook). That +way if you no longer want to receive email from a given sender, you +can easily filter it out. + +Additionally, by having site-specific email addresses you can also +tell when a breach of security happened. If I tell Home Depot my email +address is home-depot@myspam.example.com and I start receiving spam +from Nigeria on that address I know that Home Depot has had a security +breach. I can use that to inform Home Depot, Twitter, my friends that +there's been a breach, in addition to checking credit cards for +possible fraudulent charges. + +In short, having private email addresses per organization allows you +to keep tabs on your private life and help keep you more secure. + +It would be remiss to not mention spamgourmet.com, a wonderful service +that was the inspiration for this code. I've been a happy spamgourmet +user for many years, but unfortunately it has some problems this +software attempts to address: + +1) spamgourmet.com and its various addresses are too well known. By + hosting this on your own domain you can prevent, for instance, + Facebook from filtering your email address. +2) spamgourmet addresses are very long and hard to communicate over + the phone or when filling out forms at, say, the doctor's + office. This is attempting to provide much shorter addresses that + will raise fewer eyebrows and communicate more easily. + +* HOW IT WORKS +Once the software is installed (see INSTALLATION, below), it will +start receiving all email directed at it (such as by procmail or +sieve), and it will examine the destination address (i.e., "To" +header) to determine whether it should deliver the email to the final +recipient or not. + +SpamCat relies on your MTA delivering mail from your spam domain to a +real email address that can be used for IMAP/POP/etc. This can be +accomplished in any number of ways based on your MTA/LMTP/LDA setup; +an example for Postfix/Dovecot is below. + +When SpamCat receives a message it looks at the username (the +left-hand of the "@" in an email address) to determine the +sender. Thus, "foo@bar.com"'s sender is "foo". + +Once the sender is determined SpamCat will see how many messages are +remaining for that sender, and if the sender has no remaining messages +then the message is thrown away. + +If the sender has messages remaining then the message is delivered +as-is with the exception that the Subject header shows how many +messages are remaining and the total number of messages available +(e.g., "Subject: XANAX FOR NIGERIA - [19/20]" shows that there are 20 +total messages from this sender, and there are 19 remaining). + +* RECOMMENDED USAGE +1) Create your own spam-handling domain (e.g., "spam.example.com") +2) Use private email addresses in that domain anywhere you're asked + for an email address (e.g., giving ShopRite an address of + "shoprite@spam.example.com") + +* PREREQUISITES +1) Perl 5 +2) Email::Simple +3) SQLite 3 +4) DBD::SQLite + +* INSTALLATION +1) See INSTALL to install the library and spamcat executable. +2) Once the spamcat executable is installed you'll need to add it to + your procmail, sieve, or some other similar device that takes an + email on standard input and expects local delivery. +3) You will also need to create a config file for spamcat (see + config/spamcat.conf for an example) somewhere that can be read by + spamcat. +4) Make sure you pass in the spamcat.conf file to spamcat via the "-c" + argument (e.g., "spamcat -c /home/me/etc/spamcat.conf"). + +* EXAMPLES +** Postfix +*** main.cf +Postfix needs to know that the spam domain should be handled locally. + +#+BEGIN_COMMENT +virtual_mailbox_domains = spamcat.domain somewhere.else +#+END_COMMENT + +*** virtual aliases table +Make sure postfix can route the spam domain to the user who should +receive it. + +#+BEGIN_COMMENT +@spamcat.domain hidden-address@somewhere.else +#+END_COMMENT + +** Dovecot/Sieve +The sieve file for the user which recieves mail for the spam domain +should pipe the email into spamcat, which will handle final delivery +for the spam domain. + +#+BEGIN_COMMENT +require ["fileinto", "envelope", "vnd.dovecot.pipe"]; + +if address :contains "to" "@spamcat.domain" { + pipe :try "spamcat" ["-c", "/path/to/spamcat.conf"]; + fileinto "Junk"; +} +#+END_COMMENT +** DNS +The MX record for your spam domain should point to the MTA that hosts +spamcat. + +#+BEGIN_COMMENT +spamcat.domain MX 10 yourmta.domain. +#+END_COMMENT |