The_Dev_Crypt

How to check mail queue?

$postqueue -p

How to flash/resend the queue mails?

$postqueue -f

How to check the basic config?

$postconf -n

How to check whole config?

$postconf

How to make all queue as renew queue? Continue reading Postfix cheat-sheet

Postfix is free and powerful MTA. You can easily configure Postfix to block spam. You need to add following directives to /etc/postfix/main.cf file:

disable_vrfy_command = yes : Disable the SMTP VRFY command. This stops some techniques used to harvest email addresses.

smtpd_delay_reject = yes : It allows Postfix to log recipient address information when rejecting a client name/address or sender address, so that it is possible to find out whose mail is being rejected.

smtpd_helo_requi
red = yes : Require that a remote SMTP client introduces itself at the beginning of an SMTP session with the HELO or EHLO command. Many spam bot ignores HELO/EHLO command and you save yourself from spam. Following lines further restrictions on HELO command:
smtpd_helo_restrictions = permit_mynetworks,
reject_non_fqdn_hostname, Reject email if remote hostname is not in fully-qualified domain form. Usually bots sending email don’t have FQDN names.
reject_invalid_hostname, Reject all bots sending email from computers connected via DSL/ADSL computers. They don’t have valid internet hostname.
permit Continue reading Postfix configure anti spam with blacklist

In this tutorial I will show how you can set up a Postfix mailserver as a backup mail exchanger for a domain so that it accepts mails for this domain in case the primary mail exchanger is down or unreachable, and passes the mails on to the primary MX once that one is up again.

I do not issue any guarantee that this will work for you! Continue reading Setting Up Postfix As Buckup MX