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
virtual_alias_domains, and domains that
resolve to IP addresses listed in
proxy_interfaces. Your domain must be
listed in one of these parameters.
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.
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.
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