block foreign language

floyd

floyd

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Mar 29, 2005
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Is there an way for exim to block certain languages. I can only read English so there is no point in me getting foreign language email especially the spam that gets through. I can't read it so I may as well reject it.
 
Floyd,

I did this successfully before with Spamassassin, for specific domains. I don't have on any of my newer servers but plan to re-implement it. And I think it can be done server-wide. I don't remember.

http://www.yrex.com/spam/spamconfig.php

Language Options
Accepted Languages: SpamAssassin can analyze the text and character set of a message and make an educated guess at the language being used. Select the languages you receive legitimate mail in, and messages in other languages will have their spam score increased. By default all languages are accepted. (ok_locales, ok_languages)
Click to expand...

Regrettably server load will take a hit, as usual.
 
This post might be of interest:

http://www.exim-users.org/forums/archive/index.php/t-35226.html

It details an exim acl that blocks 8bit ascii characters on the subject line. I have seen several versions... but would not know which to trust.

There is one that checks for AT LEAST 4 8bit characters together, and then rejects. That is so european users don't get mistakenly bumped for using one or two accents in a sentence, I guess.

Here:



From the article:
8 bit characters in subject line:
About 30% of the spam origins in China, Taiwan or other Asian countries these days. If you are sure that you can't read Chinese then you can reject mail which has a lot of 8 bit characters (not ASCII) in the subject. Some MTAs have a separate configuration option for this but you can also use regular expression matching on the header:

/^Subject:.*[^ -~][^ -~][^ -~][^ -~]/

This will reject email which has more than 4 consecutive characters in the subject line which are not in the ASCII range space to tilde. If you are not familiar with regular expressions then learn them, you will need them (See LinuxFocus article 53). Both exim and postfix can be compiled with perl regular expression support (see www.pcre.org). Perl has the most powerful regular expressions.
This method is quite good and keeps out 20-30% of the spam-mail.
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At least in Spanish, we don't have multiple high ascii characters lumped together. We might have something like, "descripción"... but never will you see "descripcíón" (two accents).

That last one is not in exim acl format... so I wouldn't even know where to begin to adapt it. Perhaps somebody smarter than me would care to jump into this conversation.
 
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I did this successfully before with Spamassassin
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I have done this too but I don't like running SA. Too much overhead for too little benefit.
 
For anybody else bumping into this thread and looking to block emails from China, etc.

This RBL can block by country of origin... could be of some utility:

http://www.cluecentral.net/rbl/

The possibility for false positives seems extremely high. I would not use this directly on exim.conf, users might actually want their Chinese, Russian, Korean email because of business/personal reasons.

Now... you could add it to your personal SpamAssassin prefs file to add points as per:

http://improbable.org/chris/index.php?ID=109

rather than to the entire server.
 
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