Basic Postfix Setup

1. Set myhostname to the FQDN of your server. For example

myhostname=myserver.example.com

2. Add the following to your /etc/mail/main.cf file

# Allow only ourselves as mynetworks

mynetworks=127.0.0.1

# This disables the vrfy command which can be used by spammers to verify if an email addy exists

disable_vrfy_command=yes

# Be more strict about how many errors we can get before we give up on the client

smtpd_soft_error_limit=5
smtpd_hard_error_limit=10

smtpd_data_restrictions=
reject_multi_recipient_bounce,
reject_unauth_pipelining

smtpd_etrn_restrictions=
permit_mynetworks,
reject

# Require sending server helo to us

smtpd_helo_required=yes

smtpd_recipient_restrictions=
reject_non_fqdn_recipient,
reject_unknown_recipient_domain,
permit_mynetworks,
reject_invalid_hostname,
reject_non_fqdn_hostname,
reject_unauth_destination

smtpd_sender_restrictions=
reject_non_fqdn_sender,
reject_unknown_sender_domain

# Make sure envelope addies contain <>

strict_rfc821_envelopes=yes