When would I use the 'Use source Reply-To address' option in the 'Email Address Options' window? (NETIQKB1384)

goal
When would I use the 'Use source Reply-To address' option in the 'Email Address Options' window?

fact
Exchange Migrator 1.x

fact
Exchange Migrator 2.x

fix
This option will most often not be chosen because the default option is "Use Translated Reply-To". However, you may choose to use this option if you plan on keeping the same SMTP namespace in your target environment.

Formerly known as NETIQKB1384