spam filter and MX records

[barber.greg at gmail.com]

Well it's kind of a strange setup the mailer and the webmail interface
all reside on machine. Prior to the filter being put in place no MX
existed for this machine it was only an A record set to the email
domain so instead of being mail.xyz.123.edu or mx.xyz.123.edu it's A
record was just xyz.123.edu. I thought in a situtation like this the
change would be warranted in case the filters went offline foreign
mailers would sense that xyz.123.edu was down and requeue the message
instead of delivering straight to xyz.123.edu via the A record.