config files in /etc/postfix
logs in /var/log/maillot

postfix reload		# after doing changes to config files
postfix flush 		# churn thru the mail backlog
mailq			# check the mailq

postconf -d    # show default param for postfix 
postconf -d  | grep mydomain
postconf -d  | grep myhost 

postconf -n 		# to find out what settings are overruled by your 
postconf mail_version	# To find out what Postfix version you have, execute the command 

address rewritting bible :)

mascarade is to hide some early portion of the domain name, 
eg strip to

/etc/postfix/canonical			# change domain address in both sender and recipient
					# main for username to first.last, 
					# but should be able to specify domain as in eg of sender-canonical

/etc/postfix/sender-canonical		# sender only, need to enable clause in  
					# eg content:

/etc/postfix/recipient-canonical	# eg:	root

after update to the file, recreate hash (or dbm) as:
sudo postmap /etc/postfix/sender-canonical

Specify dbm instead of hash if your system uses dbm files instead of db files. To find out what lookup tables Postfix supports, use the command "postconf -m".

Execute the command "postmap /etc/postfix/relay_recipients" whenever you change the relay_recipients table.

Execute the command "postmap /etc/postfix/transport" whenever you change the transport table.

Example for cluster head node (which act as relay host for all compute nodes):

mydestination = $mydomain, $myhostname, localhost.$mydomain
mynetworks =,,
inet_interfaces = all
append_dot_mydomain = no
sender_canonical_maps = hash:/etc/postfix/sender-canonical
recipient_canonical_maps = hash:/etc/postfix/recipient-canonical
relayhost =
mydomain =
myorigin =


interesting command and script to delete deferred mail.

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