So I tried to sign up for the bug tracker. No email. Tried again a couple of days later. No email. Went and looked at my mail server:
Aug 1 04:46:07 herd postfix/smtpd[7508]: NOQUEUE: reject: RCPT from smtp82.iad3a.emailsrvr.com[173.
203.187.82]: 554 5.7.1 <
[email protected]>: Sender address rejected: Domain MX in loopback network;
from=<
[email protected]> to=<MY_ADDRESS> proto=ESMTP helo=<smtp82.iad3a.emailsrvr.com>
... Uh. Pretty sure "example.com" is presumptively invalid for actual outgoing mail. I bet a lot of people's spam filters are dropping these, because "domain MX in loopback network" is indeed a very good reason to assume that the address cannot possibly be valid, and it is a very good idea to reject mail from invalid addresses unconditionally.
