I'm having trouble setting up a mail server, after following this tutorial I am still unable to send email to anyone outside of my server.

I have installed and configured PostFix, Dovecot, Squirrellmail

The exact error message I get is:

Transaction failed 554 5.7.1 email@example.com: Relay access denied

There could be an issue with my PostFix config file below (mail_version = 2.9.3)

# See /usr/share/postfix/main.cf.dist for a commented, more complete version

# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtpd_tls_cert_file = /etc/ssl/certs/smtpd.crt
smtpd_tls_key_file = /etc/ssl/private/smtpd.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

myhostname = mysite.com
mydomain = mysite.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
relayhost = 
mynetworks =, 12.33.444.55 #not the real IP
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
home_mailbox = Maildir/
mailbox_command = 
smtpd_sasl_local_domain = 
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination
smtp_tls_security_level = may
smtpd_tls_security_level = may
smtpd_tls_auth_only = no
smtp_tls_note_starttls_offer = yes
smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom

Any help would be very appreciated.

  • Unless the machine or network you are configuring this for is exmaple.com that looks like the correct error that should happen when trying to relay mail for that domain. – dobey Dec 13 '13 at 20:48
  • @dobey example.com is an example email, my god, I'm not going to display my real email address. – mk_89 Dec 13 '13 at 21:45

You have

mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

which translates as

mydestination = mysite.com, localhost.mysite.com, localhost, mysite.com

Sending an email to somewhere@example.com is relaying. You can control the behaviour with smtpd_recipient_restrictions. You have reject_unauth_destination which means that relaying is disabled (see here for more details), unless one of the permit_* before matches. In this case you have permit_sasl_authenticated,permit_mynetworks, the second one means you need either to send the email directly from the hosts (in fact any host in mynetworks), or to authenticate yourself (permit_sasl_authenticated).

TL;DR: you need to authenticate if you want to send emails from a remote machine to an other domain.

  • So confusing :-/ wish email was simpler. – Oliver Dixon Feb 1 '16 at 7:58

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