Author: J.Simpson (23 Nov 04 3:50am)
there's no need to delegate sub-domains. just make up a bogus hostname that looks like a legitimate mail server name, but has nothing to do with the actual delivery of your domain's existing mail.
for example, let's say you're running BIND, and trying to donate "mail3.decibel.org" to the cause...
in the zone file for "decibel.org", add this line (substituting whatever hostname they told you to point your mail to)...
mail3 IN MX 0 mx9.mxmailer.com.
if you've already set up a sub-domain, you need to remove it from your named.conf file. also remove any NS records you may have added to the zone file in order to set up the delegation. remember to increment the serial number in your zone file, and restart named.
this will be propogated to your secondary servers without any trouble, the automated testing will be happy, and your donated MX will be doing a service to the world.