[OT] Mail problems (was Re: Bug#246305 ...)

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On May 1,  1:42am, Clint Adams wrote:
}
} BTW, I don't know if it's just me, but verizon.net is rejecting direct
} mail to Bart.

Several months ago Verizon instituted a "callback" policy -- their mail
servers wait for the MAIL FROM, then attempt to look up an MX record for
that address and make an SMTP connection to that MX.  If they connect
to the MX, they issue MAIL FROM:<> and RCPT TO:<the MAIL FROM of the
message destined for verizon> and expect a 250 OK, at which point they
hang up.

They then reject the message with a 450 temporary failure if there is no
MX (so hosts with only an A record are out of luck) or permanently with
a 550 if there was no 250 OK to their callback.

Some sysadmins consider such callbacks abusive in their own right, and
others consider them to be a sign of accept-then-bounce of worm spew, so
they configure their systems to stop answering verizon's callbacks, and
the result is that no mail can reach verizon from those domains.

I don't know what the specific situation may be for Clint.  However, I
*did* get two copies (one on-list, one direct) of the message from Clint
that is excerpted above.