[PLUG] Can I modify email headers with Perl script...

[Michael C. Robinson]

Apparently I'm not supposed to reject email when there is no reverse PTR
record.  Can I have my Perl script add a line to the email headers that
says essentially, reverse resolution failed?  I'm using iptables QUEUE
on SMTP connection packets.  What I'm asking is, what is the extent of
what I have to work with?  If I have headers, how do I access them to
change them?  I know I can grab the destination and source IP addresses,
but do I have email headers yet?  Maybe I should just query a list of
IP's which don't reverse resolve that I should relay, a white list.

Is there a Perl module that will allow me to query DNS blacklist
servers?  If so, what is the module called and which DNS blacklist
server do I want to query?