Internal Use Only
Group members:
Nick Principe / naprinci@gmail.com / AIM: mahoubaka
Ken Ganong / kjganong@ncsu.edu / AIM: C4P0droid
- block domains or even top-level domains "known" to be large senders of spam
- require users to request permission to send you e-mail (eg Earthlink spam blocker)
- Charge for e-mail sent
- opt-in for commercial email
- domain authentication
- bounties
- the "goodmail" approach
- bond with escrow agencies
- client-side filtering
huge paper on this subject
Spam Prevention Techniques
Comparison of Techniques
Technique
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Pros
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Cons
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Authors' Rating
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Block domains of "known" spammers
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- 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)
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- Some spam still gets through, especially from new sources (put in percent from sbl/sbl-faq)
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Require users to request permission to send you e-mail (e.g. Earthlink spam blocker)
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- Robots cannot easily send spam
- False identity doesn't work
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- Emergency emails don't send quickly
- Time consuming to send short notes
- Impossible to implement correctly
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Charge for e-mail sent
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- Forces targeted selection
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- Defeats the purpose of email
- Where does the money go?
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Opt-in for commercial email
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- Companies can send advertisements without sending spam
- Users can freely restrict the influx of mail from their many online affiliations
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- There are many fraudulent emails in which the opt-out link sends you to an unwanted web page.
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Domain authentication
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- Very little spam gets through
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- 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
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Bounties
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- Gets rid of big spammers with incentive
- Possible deterrent
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- Costs government (tax-payers) money
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The "Goodmail" approach
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- Mass emails cost money so mass spammers don't work
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- Companies can bypass the spam filter by paying money
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Bonds with escrow agencies
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pro
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con
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Client-side filtering
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pro
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- Only as good as user or algorithms/heuristics at identifying spam
- Spam emails are stopped, they are simply not read.
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Technique Details
Block domains of "known" spammers
- Summary point 1
- Summary point 2
- Link 1
Require users to request permission to send mail
Charge for email sent