Using valid emails

[Chris Angelico]

On Tue, Aug 2, 2016 at 2:05 AM, D'Arcy J.M. Cain <darcy at vex.net> wrote:
>> probably your SMTP server, will tell you. In contrast, your valid
>> email address will become the target of many spam emails even if you
>> manage to block them. It will also be used as the source of spam so
>> somebody at vex.net may be fooled into believing that they are
>> receiving a proper email.
>
> 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.

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

ChrisA