Use letsencrypt to set up smtpd TLS

[djmitche]

We have this disabled on the mx jail right now..

[djmitche]

One option is to set up a webserver and just use that cert; the other is to do DNS verification.

[djmitche]

12:18:30 <•bdbaddog> djmitche: letsencrypt has wildcard certs now. so you could get *.buildbot.net cert on the webserver and then pull or push it to smtpd server?

[djmitche]

This may help with

May 29 16:32:32 mx postfix/smtp[98615]: 261D829A718: host gmail-smtp-in.l.google.com[74.125.195.27] said: 421-4.7.0 [140.211.10.235      15] Our system has detected an unusual rate of 421-4.7.0 unsolicited mail originating from your IP address. To protect our 421-4.7.0 users from spam, mail sent from your IP address has been temporarily 421-4.7.0 rate limited. Please visit 421-4.7.0  https://support.google.com/mail/?p=UnsolicitedRateLimitError to 421 4.7.0 review our Bulk Email Senders Guidelines. n23-v6si4908006pgc.366 - gsmtp (in reply to end of DATA command)

too.