version : postfix-2.2.5-3.rhel4.rpm
OS : Centos 4.2
local host : chinamail (only for intranet, not fqdn)
public domain : newhonest.com

I have my new postfix set up recently for my intranet. I have some
restriction settings in main.cf

smtpd_recipient_restrictions = check_sender_access
hash:/etc/postfix/restricted_senders, permit_mynetworks,
reject_unauth_destination

#
smtpd_restriction_classes = local_only nh_only
local_only = check_recipient_access hash:/etc/postfix/local_domains,
reject_unauth_destination
nh_only = check_recipient_access hash:/etc/postfix/nh_domain,
reject_unauth_destination
#

(nh_domain, local_domains and restricted_senders are created and postmap-ed)
With the above config, everything is working well, except when email is sent
to our own domain (newhonest.com, but bot chinamial), the sender's address
looks like sender@chinamail. In order to make it looks like
sender@..., I added the following line, and created the file
/etc/postfix/generic, the postmap it:

#
smtp_generic_maps = hash:/etc/postfix/generic
#

After this setup, emails sent to otherusers@... will be having
"aaazzzaaazzzaaazzzaaazzzaaazzz" in the body.

content of generic :

sender_a sender_a@...
sender_b sender_b@...
etc

I have seen some posts on forums claiming that this may be caused by virus,
but I don't think so. What's wrong with generic?

Jason