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diff --git a/libc/msdos/xxx/mailfilter.html b/libc/msdos/xxx/mailfilter.html new file mode 100644 index 0000000..035c26e --- /dev/null +++ b/libc/msdos/xxx/mailfilter.html @@ -0,0 +1,153 @@ +<!-- X-URL: http://www.cs.helsinki.fi/~wirzeniu/mailfilter.html --> +<BASE HREF="http://www.cs.helsinki.fi/~wirzeniu/mailfilter.html"> + +<html> +<head> +<title>Lasu's mail filters</title> +</head> +<body> + +<strong>Note: I've updated this page a little bit, but it still describes +the previous version of the filter. The new filter is quite similar to +the old one, but has easier configurability, and is (by default) rather +less aggressive.</strong> + +<h1>Lasu's mail filters</h1> + +<p>This page explains how I use procmail to filter +my mail. Perhaps the most interesting part is how I reject mail from +strangers in order to avoid getting spammed. This is not an introduction +to spam or why it's bad, or to procmail or mail filtering; see links at +end for some suggestions, but I do assume you're able to implement the +filtering on your own. + +<h2>The approach</h2> + +<p>My filtering approach is like this: +<ol> +<li> If the sender is on the blacklist, delete the letter. +<li> Put mailing lists in their own folders. <em>This must be done + correctly!</em> Otherwise the mailing list mail is treated as + junk e-mail. +<li> Put local administrative e-mail in its own folder. I administrate my + own Linux + box. This catches mail from system crontabs, news log summaries, + and so on. (Maybe not relevant to you.) +<li> At this point, it should be personal mail. Check that the To or Cc + headers address me. If not, delete the mail. +<li> Put bounce messages in their own mailbox. +<li> If the sender is on my whitelist: + <ol> + <li> If I'm on vacation, send back automatic response. + <li> Put the letter in inbox. + </ol> +<li> If the subject includes password, put in special folder for + unknown people. +<li> Otherwise, autoreply with request to use password and delete the mail. +</ol> + +<p>Instead of deleting the unwanted mail, it is also possible to just store +it in a special folder. You should do this while testing the setup, so that +you don't lose any important mail due to errors. It's best to use separate +folders for each case; I have folders no-password and new-OTHER, but feel +free to use other names. + +<p>When using this scheme, it is imperative to put all addresses you send +mail to on your whitelist or else to put the password in the subject. +Otherwise, you will annoy people. I have an automatic setup for the +MH mailer. + +<h2>Problems</h2> + +<p>My approach has some problems: +<ul> +<li> If someone sends you mail using the Bcc header, it will be treated as + junk, since your address won't be visible in the To or Cc headers. + The Bcc header is removed before the mail is sent, so there is + no way to distinguish interesting Bcc'd messages and junk mail. + This is not really a problem for me, because I almost never get + Bcc'd mail, and when I do it is via one specific mailing list. +<li> Subscribing to mailing lists. You can't filter away the list until + you know what the headers look like, so you have to turn off + the check for personal mail until you can get the list filtering + to work. (The new version of the filter attempts to put stuff from + unknown mailing lists to a separate folder, but better safe than + sorry.) +<li> Spam sent to mailing lists won't be filtered away. This is not too big + a problem, because many mailing lists + now only allow subscribers to post to avoid spam. +<li> Not all bounce messages are filtered correctly. Unfortunately, there + are about as many bounce message formats as there are mail + transport programs. This is a real problem, because it's not + really a good idea to not lose bounce messages. It also opens + a glaring hole, because spammers can make their junk look like + bounce messaages. +<li> If the filter starts acting up, you'd better know Procmail, or be + prepared to drop it at once. +</ul> + +<h2>Alternative methods</h2> + +<p>Many ways to fight junk mail have been proposed. Below is a list of +a few of them and the reasons why I don't do that. + +<ul> + +<li><strong>Just delete them.</strong> +This is what I've been doing. It takes time to read enough of a letter + to positively identify it as junk. Not a whole lot of time, but + doing something unproductive several times a day is not fun. + It is annoying and lowers my work morale. I do computers because + it's fun, and junkmail makes it not fun. + +<li><strong>Complain to sender or in public.</strong> +This takes time. I don't want to spend time on dealing with junk. +Using tools to automate most of the complaint process is not good +enough, since no tool is able to decode forged headers completely, +and sending the complaints to the wrong address is <em>wrong</em>. + +<li><strong>Just filter away known baddies.</strong> +I won't know who they are, unless I get the mail, and by then it's too + late. Actually, I could read suitable newsgroups and mailing lists + and find reports of spammers, but again, it takes time I don't want + to spend. It also never ends, since the most persistent spammers + change accounts often, and there are hordes of new spammers on + the horizon. + +<li><strong>Use a service that removes your address from spammers' lists.</strong> +Which one? How do I know they're reputable? What guarantee do I have that + the spammers use the services? Also, many of them have + been shown to be just another way to harvest e-mail addresses. + +<li><strong>Use a munged mail address in public.</strong> +This causes postmasters (the people who keep the mail systems running) +extra work. Not polite, and counter-productive on the long run. + +</ul> + +<h2>Related links</h2> +<ul> +<li> <a href="mailfilter2.tar.gz">My mail filter</a>. +<li> <a href="mailfilter-mh.html">My MH setup to automatically put addresses + I send to to the whitelist.</a> +<li> <a href="ftp://ftp.informatik.rwth-aachen.de/pub/packages/procmail/procmail.tar.gz">Procmail source code</a>, + if you system doesn't have procmail installed. +<li> <a href="http://www.jazzie.com/ii/faqs/archive/mail/filtering-faq/">Mail Filtering FAQ</a>, + for more information about mail filtering in general. +</ul> + +<h2>Feedback</h2> + +<p>I'd be glad to hear any suggestions on how this filtering scheme +can be improved. Don't hesitate to tell me if you have ideas on solving +the above problems or if you can think of a new problem. I'd also be +grateful if tell me if you use this filtering scheme so that I can tell +you about important updates. I'd also like to hear of alternative filtering +schemes, especially for people using non-Unix systems. Follow the link +at the bottom before mailing, so you'll know how to avoid my filtering. + +<p>(22 September 1997, +<a href="mail-to-lasu.html">Lars Wirzenius</a>) + +</body> +</html> |