Re: mangled IP address causing bounce

> TMDA seems insistent on mangling proper IP address notation by replacing the
> square brackets with underscores.  Is there any way to correct this
> behavior?

I got to the bottom of this problem, and it's a Postfix not a TMDA
problem.  Postfix was passing a mangled RECIPIENT (and DOMAIN)
environment variable to TMDA.

According to the manpage for Postfix local, "Characters that may have
special meaning to the shell are replaced by underscores.  The list of
 acceptable characters is specified with the command_expansion_filter
configuration parameter."

postconf reveals the default setting for command_expansion_filter does
not include brackets.  Setting command_expansion_filter to include [
and ] in main.cf solved the problem.  Hopefully with the proper domain
checks in place this doesn't open up any security holes.