If you sent me email and didn’t get a response, it may be due to your service provider’s use of blacklists.
It happens to me now and again where someone send me email, and I reply, and I get a returned-to-sender email with something like this:
reason: 550 Your host is locally blacklisted, contact firstname.lastname@example.org
The thing is, I use sendmail on my desktop machine. I have it set so it works only from my desktop machine. (And there is of course other security on my LAN.)
I guess this means that somewhere there’s a blacklist that includes localhost 127.0.0.1.
Nuts! I think these blacklists totally suck.