We currently have an internal email system using the domain
<internal.com> . Our regular domain is <example.com>. Up until a
month ago we were using sendmail and I thought I had figured out how to
do the masguerading of the internal domain. But I am getting some of
my users email bounced back because they are still showing in the
headers as
Sender : <user1@internal.com>.


mydomain = example.com
myorigin = $mydomain
mydestination = $myhostname, localhost.$mydomain, localhost,$mydomain,
example.com,localhost.localdomain,internal.com

canonical_maps = hash:/etc/postfix/canonical

masquerade_domains = internal.com
------------------------
#postmap /etc/postfix/canonical
----------------------------------
/etc/postfix/canonical
@internal.com @example.com