nanog mailing list archives
Re: Misguided SPAM Filtering techniques
From: Tony Finch <dot () dotat at>
Date: Mon, 22 Oct 2007 19:17:29 +0100
On Sun, 21 Oct 2007, Nathan Ward wrote:
http://www.ietf.org/rfc/rfc2476.txt
Note that this has been superseded by RFC 4409. More recommendations about the operational and policy issues are laid out in http://www.ietf.org/internet-drafts/draft-hutzler-spamops-08.txt which will soon be published as RFC 5068. Sadly it doesn't say much about the rationale for its recommendations, especially why it's not OK to block 587 even when it might be OK to block 25, because talk of port blocks rapidly descends into flame wars. However it's fairly clear if you think about who suffers from spam sent via port 587. The key point is that the operators of an MSA has a strong incentive to keep their users clean, or at least their mail flows clean, because any spam sent via their MSA will (typically) go out of the same relays whether the client is on site or roaming or using the webmail service. Therefore reputation problems (AOL spam complaints, blacklistings, etc.) will accrue where it hurts. The situation is very different for port 25 email, becase the target MTA has no control over the senders. Access providers don't care about their access networks having bad spam reputations because the pain doesn't affect them directly enough. Tony. -- f.a.n.finch <dot () dotat at> http://dotat.at/ SOUTHEAST ICELAND: NORTHERLY 5 AT FIRST IN EAST, OTHERWISE SOUTHEASTERLY 4 OR 5 INCREASING 6 OR 7. MODERATE OR ROUGH. RAIN LATER. GOOD, OCCASIONALLY MODERATE LATER.
Current thread:
- Misguided SPAM Filtering techniques Owen DeLong (Oct 20)
- Re: Misguided SPAM Filtering techniques Nathan Ward (Oct 20)
- Re: Misguided SPAM Filtering techniques Adrian Chadd (Oct 20)
- Re: Misguided SPAM Filtering techniques Nathan Ward (Oct 20)
- Re: Misguided SPAM Filtering techniques Tony Finch (Oct 22)
- Re: Misguided SPAM Filtering techniques Adrian Chadd (Oct 20)
- Re: Misguided SPAM Filtering techniques D'Arcy J.M. Cain (Oct 21)
- Re: Misguided SPAM Filtering techniques Dave Pooser (Oct 21)
- Re: Misguided SPAM Filtering techniques D'Arcy J.M. Cain (Oct 21)
- Re: Misguided SPAM Filtering techniques Sean Figgins (Oct 22)
- Re: Misguided SPAM Filtering techniques Patrick W. Gilmore (Oct 22)
- Re: Misguided SPAM Filtering techniques Sean Figgins (Oct 22)
- Re: Misguided SPAM Filtering techniques Valdis . Kletnieks (Oct 22)
- Re: Misguided SPAM Filtering techniques Sean Figgins (Oct 22)
- Re: Misguided SPAM Filtering techniques Dave Pooser (Oct 21)
- Re: Misguided SPAM Filtering techniques Nathan Ward (Oct 20)
- Re: Misguided SPAM Filtering techniques Al Iverson (Oct 22)
- Re: Misguided SPAM Filtering techniques Valdis . Kletnieks (Oct 22)