Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From: "D'Arcy J.M. Cain" <darcy@Vex.Net>
Newsgroups: comp.lang.python
Subject: Re: Using valid emails
Date: Mon, 1 Aug 2016 12:40:14 -0400
Organization: Vex.Net
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References: <nngdns$um1$1@dont-email.me> <579c2095$0$22142$c3e8da3$5496439d@news.astraweb.com> <nnhuni$op$1@dont-email.me> <20160730103937.6b993ad5@imp> <mailman.53.1469889592.6033.python-list@python.org> <nnig8c$nab$1@dont-email.me> <20160730131105.443fff84@imp> <mailman.57.1469898675.6033.python-list@python.org> <g32spb5srjo5qakib683avs10hfqb5v9k7@4ax.com> <20160731115347.3c2a8344@imp> <20160731120434.3f587ad9@imp> <mailman.78.1469981083.6033.python-list@python.org> <soqupbdkik0bna68ql8ae33a9fjb4vbpk7@4ax.com> <20160801120515.654f2737@imp> <CAPTjJmoc2_kHw6+=ykB8CaCKkMPLAyhfU-nm6VagGRfD9wR6Tw@mail.gmail.com> <20160801124014.214444c2@imp>
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On Tue, 2 Aug 2016 02:22:50 +1000
Chris Angelico <rosuav@gmail.com> wrote:
> > I'm a little insulted that you think that I would ever allow
> > someone to send mail to Vex.Net pretending to be from Vex.Net.
> > That's just too easy to detect and block.  Try it.  
> 
> vex.net. 10800 IN TXT "v=spf1 mx -all"
> vex.net. 10800 IN MX 10 mail.vex.net.
> mail.vex.net. 10800 IN A 98.158.139.68
> 
> So, if you're not sending mail from 98.158.139.68 and you claim to be
> vex.net, you should be blocked.

Exactly.  I also have a further check.  If you try to send me email
pretending to be from Vex.Net you get a "5xx Yah Right" error.

> Unfortunately, a lot of domains don't have SPF records, or have very
> convoluted ones (check out gmail.com's SPF for instance).

I can only fix my little corner of the Internet.

-- 
D'Arcy J.M. Cain
System Administrator, Vex.Net
http://www.Vex.Net/ IM:darcy@Vex.Net
VoIP: sip:darcy@Vex.Net