This shouldn't be this hard, but I'm unable to get e-mail delivered locally on my F15 system. Messages sent to root, or to local users by other local users (i.e., they are not supposed to go out to my ISP for handling) indeed are trying to go out the door for delivery, but they hang--mailq says:
p5B8BmS6024005 4220 Sat Jun 11 04:11 <email@example.com>
(Deferred: Connection timed out with mydomain.com.)
Eventually, they time out and are returned to the local postmaster account--which is aliased to me ('tkevans')--and they get delivered locally! However, root is also aliased to me, and messages to root suffer the same 5-day hang.
These hanging messages are all local sys-admin stuff (logwatch and the like), and there aren't any other real local users.
I don't use local sendmail for external mail delivery and receipt; instead, I use Thunderbird as an IMAP client to my ISP. All the mail Thunderbird generates works perfectly well, since it's going outside; cc's to me are also delivered via IMAP and work ok.)