North American Network Operators Group

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Re: Misguided SPAM Filtering techniques

  • From: Dave Pooser
  • Date: Tue Oct 23 01:55:52 2007

> I use an authenticated TLS-protected mailhost at home for submitting my
> email for delivery.  Unfortunately, networks have taken to:
> outright blocking 25 and 587 except to their own servers.

Back in the day AT&T dial-up blocked port 25 outgoing (except to their own
servers) for the first month; after that, a user could request an unblock. I
believe the SBC/AT&T Borg does the same thing with dynamic DSL IPs.

It seems to me that blocking port 25 by default and unblocking on request
would be an ideal low-maintenance solution that would reduce spam
considerably, and has the added benefit of being on-topic for NANOG.
Dave Pooser, ACSA
Manager of Information Services
Alford Media