Postfix: The Definitive Guide

Appendix D. Frequently Asked Questions

I can’t seem to receive messages. What does this error mean: “<[e-mail]>: mail for example.com loops back to myself”?

Postfix reports this error when a DNS reply points to your mail server, but Postfix has not been configured to accept mail for the domain. Postfix accepts mail for domains listed in mydestination, relay_domains, virtual_mailbox_domains, virtual_alias_domains, and domains that resolve to IP addresses listed in inet_interfaces and proxy_interfaces. Your domain must be listed in one of these parameters.

When I make changes to configuration files or lookup tables, do I have to reload Postfix?

It depends on the type of file you are changing. Changes in files that Postfix reads into memory at startup require a reload. Examples of such files are main.cf, master.cf, and any lookup table using regular expressions. DB or DBM files are not read into memory and don’t require reloading Postfix when they are changed.

Is there some kind of “include” directive for main.cf?

No. Most administrators with complex configurations create a Makefile that will cat the necessary files together. If you have other regular administrative tasks, add them to your Makefile too. Your Makefile should have an entry that looks something like this:

main.cf: file1 file2 file3
        cat file1 file2 file3 > main.cf.new
        mv main.cf.new main.cf

Then type make main.cf to rebuild your configuration file.

How can I get confirmation of mail deliveries?

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