Postings by Abhijith Sethuraj

How to add custom headers to NDR mails?


We get bounce-back emails from mailer-daemon when one or more of the
recipient addresses are invalid. But, this information is conveyed only in
the body of the email and not inside any of the headers.

I'm aware of the bounce daemon along with setting custom bounce messages
using a template file but I'm unable to figure out a way to extract the
failed recipients and then append that onto the template file as a custom
header, say "X-Failed-Recipients". Are they present inside a special
variable of some sort that I'm missing out on?


Guidelines for headers in original message


What are the general guidelines for headers and their values that are shown
in the original message of an email? I'm particularly interested in the
'Received from: foo by bar'. Do people generally append the actual
servernames along with their IP addresses for all the hops? Or, do they
make the mails come out from a common relay server.

Also, if it's fine to make mails come from a common relay, is it a bad idea
to set $myhostname to foo.relay for all the mails from foo domain, instead
of showing all the hops? I've seen people put this as $myorigin.