Some Tips for Legitimate Senders to Avoid False Positives

Tip: use normal conversational English, be sure not to use excessive spacing and or capitalization on your subject (as this will be scanned too!)

Tip: examine exactly which rules were triggered if a message was marked as spam or nearly marked as spam. Take careful note of the points listed beside each rule name – low-scoring rules do not make much of a difference, it's the ones with high scores that need to be avoided.

Tip: if there are hits in the body of your mail-out, try rephrasing those sentences. We find that spam often uses exactly the same phrases, over and over again, so we detect specific lines of text, and in most cases, synonyms are ignored.

Tip: don't use similar techniques that spammers use to disguise key words, like spacing out the letters or placing punctuation in odd places in the words. The statistics for use of these techniques show that it occurs far more frequently in spam mails.

Tip: if a subscriber reports that SpamAssassin is blocking mails they want, and they did not ask their ISP to set it up – get them to ask the ISP to take them off the filtering list! (Spam filters should not be installed on an account unless the person wants it there, in our opinion, since even nowadays some people don't get as much spam as others. As a result, we ask ISPs to let the users enable or disable the filter.)

Tip: don't use 'bulk-mailing' tools used by spammers (i.e., advertised in spam). These are overwhelmingly used to send spam, so SpamAssassin blocks mail sent by those tools as soon as possible. In particular, if the product's feature list includes 'stealth sending' or similar, that's a danger sign.

Tip: there are several whitelisting services which lower scores for sites using SpamAssassin network tests:

• Bonded Sender ( http://www.bondedsender.org/ )
  Originators of legitimate email can now post a financial bond to ensure the integrity of their email campaign. Receivers who
  feel they have received an unsolicited email from a Bonded Sender can complain to their ISP, enterprise, or IronPort and a
  financial charge is debited from the bond.
• Habeas ( http://www.habeas.com/ ).
  They use a copyrighted piece of text that has restrictive licensing terms that forbid its use in spam combined with
  a DNS whitelist. They have committed to sue spammers who violate the Habeas license.
  Given that, as a result, we can count on mails with this token being non-spam, we're happy to give it "bonus points" and
  allow it through filters.
  

Please report any spam that is given bonus points for either of these services to the respective service.

Some useful links:

• Frugal Marketing: That's not Spam, That's My Newsletter! http://www.frugalmarketing.com/dtb/notspamnews.shtml
• SpamCon Foundation: Best practices for marketers: http://www.spamcon.org/directories/best-practices.shtml
• Bulk e-mail HOWTO: http://spam.abuse.net/marketerhelp/bulk-howto.shtml
  

Other methods for receiving "bonus points":

• HashCash ( http://hashcash.org/ )
  See http://hashcash.org/faq and http://hashcash.org/draft-hashcash.txt.
  This is a technological solution, while Bonded Sender is an economic solution and Habeas is a legal solution. Hashcash is not appropriate for large mailing lists, as it requires substantial computational power to send each email.
  
  

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