Email that won't travel more than 500 miles

Great sysadmin war-story about a university mail-system that would not transmit mail to hosts more than 500 miles away.

I logged into their department's server, and sent a few test mails.
This was in the Research Triangle of North Carolina, and a test mail
to my own account was delivered without a hitch. Ditto for one sent
to Richmond, and Atlanta, and Washington. Another to Princeton (400
miles) worked.

But then I tried to send an email to Memphis (600 miles). It failed.
Boston, failed. Detroit, failed. I got out my address book and
started trying to narrow this down. New York (420 miles) worked, but
Providence (580 miles) failed.

I was beginning to wonder if I had lost my sanity. I tried emailing a
friend who lived in North Carolina, but whose ISP was in Seattle.
Thankfully, it failed. If the problem had had to do with the
geography of the human recipient and not his mail server, I think I
would have broken down in tears.

Link

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(Thanks, Jef!)