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Re: SPF I-D for review: draft-schlitt-spf-classic-01.txt

2005-05-25 12:13:27

At 07:05 -0400 on 05/25/2005, Bruce Lilly wrote about Re: SPF I-D for review: draft-schlitt-spf-classic-01.txt:

On Wed May 25 2005 00:57, Robert A. Rosenberg wrote:

 and you are using an SPF Approved/Authorized
 > Submission/Relaying Server. If you are not allowed to use that
 > Server (due to SMTP Connection Hijacking on the part of the
 Connectivity Provider then you are out of luck - You should send from
 your Laptop via an Ethernet/WiFi connection).

If port blocking is in effect, that won't help.   That problem exacerbated
by SPF is one of the reasons SPF is harmful to Internet mail.

Deploying SPF (especially when requiring all email to be relayed by your Servers) should go hand-in-hand with having Non-Port25 Ports on the Servers (such as both MSA Port587 [SMTP AUTH Protected] and SMTP-over-SSL Port465). Requiring that your Server only be contacted on Port25 is (as you note) asking for problems (and a Catch-22 Situation) given the Existence of Connectivity Providers who Block(ie: Refuse to make the connection) and/or Hijack (ie: Force connect to their Servers) Port25 Requests to Remote Hosts.


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