Is your ISP blocking outgoing port 25?

Frank Bulk frnkblk at
Mon Jun 22 15:13:31 UTC 2009

The bootstrap question is addressed by requiring the end-user to know their
e-mail address and password.  Based on the domain name, the implementation
would reach out to https://something.domain-name.tld and download the
relevant "schema" and data for IMAP, SMTP, POP3, etc, in ordered priority.
Based on what the e-mail client could support, the desired settings would be
displayed, and upon end-user approval, applied. This could be leveraged by
RIM for their BIS, Microsoft/Gmail/etc for smartphones, and for third-party
webmail hosts such as


-----Original Message-----
From: John Levine [mailto:johnl at] 
Sent: Monday, June 22, 2009 9:24 AM
To: nanog at
Cc: frnkblk at
Subject: Re: Is your ISP blocking outgoing port 25?

>It's a pity that MAAWG or another group hasn't written a
>specification for the automatic downloading of configuration (with
>certificates, to be sure, for some kind of repudiation) and the
>update thereof, for adoption by the leading consumer e-mail clients.

MAAWG decided it's not in the standards business, but it does BCPs
pointing at standards elsewhere (mostly the IETF) that it encourages
people to follow.  Write a standard that people can use, and I don't
think I'd have much trouble getting them to endorse it.

It's an interesting design topic, particularly the bootstrap question
of how the client decides where to look for its configuration.  A lot
of this stuff is already available via DHCP, but of course a key goal
here is to set config info the last across reboots on different networks.

Followup to IETF-something, I suspect.


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