Postfix Backscatter Source by Default - Reminder

Ryan Simpkins plug at
Mon Jun 15 15:44:15 MDT 2009

It has been said many times in many places. If you're running postfix be sure
you aren't a backscatter source. Set:
parent_domain_matches_subdomains =

And possibly this as well:
relay_domains =

This came up because I didn't explicitly config it (why aren't there
reasonable defaults for postfix yet!?!?). The new PLUG server sent out 455
backscatter SPAM before I caught it.

mail from: returnmehere at
250 2.1.0 Ok
rcpt to: joe at
550 5.1.1 <joe at>: Recipient address rejected: User unknown
rcpt to: joe at
250 2.1.5 Ok

Wooops! joe at is undeliverable.

In other news, does anyone know of a presenter that would be willing to do
July 8th? We don't have anyone for July yet.


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