I have a client with SBS 2000 using Exchange to host Internet email.
Internally, everything works fine. Sending mail to the Internet works fine.
For some domains, emailing to accounts on this server does not work, or works
sporadically. Often, the emailing domain receives this message: #4.4.7 SMTP;
451 4.4.1 reply: read error.
This only seems to be happening for a few domains, but it also seems to be
increasingly affecting incoming email. Any suggestions?