CSC 379:Week 1, Group 4

Spam Prevention Techniques

• block domains or even top-level domains "known" to be large senders of spam
  • Spamhaus Block List
    • see faq also
• require users to request permission to send you e-mail (eg Earthlink spam blocker)
• Charge for e-mail sent
  • see article
  • PDF paper on charging for email
• opt-in for commercial email
• domain authentication
  • what canada has to say about it
  • seemingly useful article with links to domain authentication related concepts
• bounties
  • MSNBC article
  • another article about same event
• the "goodmail" approach
  • goodmail article
  • goodmail web page
• bond with escrow agencies
  • microsoft using following service
  • service for escrow
• client-side filtering

huge paper on this subject

Comparison of Spam Prevention Techniques

Technique Name	Pros	Cons	Our Rating
Block domains of "known" spammers	Gets rid of a large amount of spam Low chance of blocking legitimate email (sbl-faq) Mechanism to allow legitimate sources to know they were blocked (sbl-faq)	Lots of spam still gets through (put in percent from sbl/sbl-faq)	x stars!
require users to request permission to send you e-mail (eg Earthlink spam blocker)	Robots cannot easily send spam False identity doesn't work	Emergency emails don't send quickly Time consuming to send short notes Impossible to implement correctly	4
Charge for e-mail sent	Forces targeted selection	Defeats the purpose of email Where does the money go?	4
opt-in for commercial email	Companies can send advertisements without sending spam Users can freely restrict the influx of mail from their many online affiliations	There are many fraudulent emails in which the opt-out link sends you to an unwanted web page.	4
domain authentication	Very little spam gets through	Lots of false positives Could be very difficult for mail servers to initiate contact (certificate negotation crap (see SSH/SSL)) Lots of infrastructure and therefore money involved for something as simple as a mail server Hard for independents/individuals to set up their own mail server	4
bounties	Gets rid of big spammers with incentive Possible deterrent	Costs government (tax-payers) money	4
The "goodmail" approach	Mass emails cost money so mass spammers don't work	Companies can bypass the spam filter by paying money	4
Bonds with escrow agencies	pro	con	4
client-side filtering	pro	Only as good as user or algorithms/heuristics at identifying spam	4

Spam Prevention Technique Details

• Block domains...
  • Summary point 1
  • Summary point 2
  • Link 1
• Require users...
• Charge for email sent