Servers: Postfix

Keith Winston

What you need is the postfix sender_canonical lookup table. It will translate all outgoing addresses in the table to how you define them. This all has to be done as root

By the way, most mail servers will let you send to them directly as long as you have valid sender address. However, some mail servers only accept mail from machines that have DNS MX records. I send out mail directly and I've only had 1 refuse to accept my mail in the last 3 months.

in /etc/postfix/main.cf Search for

#mailbox_command = /some/where/procmail
      

And change it to your path to procmail, which is /usr/bin/procmail unless you changes the procmail installation.

in /etc/postfix/main.cf enable the body checks with this line:

body_checks = pcre:/etc/postfix/body_checks
      

Now put something in this file (/etc/postfix/body_checks):

/^(.*)name\=\"(.*)\.(hta|vb[esx]|ws[fh]|js[e]|bat|cmd)\"$/ REJECT
      

This will filter attachments (probably dangerous) of various types. Remove from the above line, whatever you want to allow.

Of course you can add some more lines to make postfix a simple spam filter:

/special offer email/       REJECT
/mortgage rates/            REJECT
      

Theo v Werkhoven

Use a service like whatismyip.com e.g.:

publicipv4=` lynx --dump http://www.whatismyip.com/ | \
egrep --only-matching -e "[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+" | head -1'

As many time as you need to, poll whatismyip.com in a cronjob, and use 'postconf -e "proxy_interface=$publicipv4"; postfix reload' to re-set the IP. Save the IP, and only change proxy_interface when you get another IP of course.

This only works when your ISP has no mandatory proxy server.