Postfix: disable local mail delivery

Question

Whenever I e-mail "root", I want it to be forwarded to root@example.org (instead of a local delivery).

However, I keep getting this:

Feb  9 17:41:54 botmaster postfix/smtp[29969]: B6E0B808F5: to=<root@botmaster.corp.flatturtle.com>, relay=none, delay=0.01, delays=0.01/0/0.01/0, dsn=5.4.6, status=bounced (mail for botmaster.corp.flatturtle.com loops back to myself)

This is my main.cf:

# 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 (by FlatTurtle)
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/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
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 = mx.flatturtle.com
#alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
local_transport = error:local delivery is disabled
mydestination = localhost
relayhost = 
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 172.27.0.0/18 85.12.6.130/32
#mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
relay_domains = /home/mx/postfix_transport
unknown_local_recipient_reject_code = 550 

smtpd_recipient_restrictions =
        permit_sasl_authenticated,
        permit_mynetworks,
        reject_unauth_destination,
        reject_unauth_pipelining,
        reject_rbl_client sbl-xbl.spamhaus.org,
        check_policy_service unix:private/postgrey,
        permit

There are a few ways to disable local delivery, but none of them seem to be working (or at least, I keep getting that message).

dig mx flatturtle.com:

flatturtle.com.     14679   IN  MX  30 mx.flatturtle.com.
flatturtle.com.     14679   IN  MX  10 mail.flatturtle.com.

dig mx.flatturtle.com:

mx.flatturtle.com.          604800  IN  CNAME   mail2.rootspirit.com.
mail2.rootspirit.com.       21600   IN  CNAME   one.rootspirit.com.
one.rootspirit.com.         21600   IN  A       95.211.44.129

dig mail.flatturtle.com:

mail.flatturtle.com.    444387  IN  CNAME   mail.rootspirit.com.
mail.rootspirit.com.    10265   IN  A       85.12.6.130

dig flatturtle.com:

flatturtle.com.     14594   IN  A   85.12.6.130

dig botmaster.corp.flatturtle.com:

botmaster.corp.flatturtle.com. 4680 IN  A   95.211.44.129

Answer 1

"mail loops back to myself" has only one cause: postfix is sending out mail to a recipient domain that it is responsible for, such as RCPT TO: me@example.org, while $myhostname is the MX for example.org.

There is no configuration to fix this, since it is what you configured.

Add an alias for root to somewhere NOT on your postfix box, such as:

root:  you@other.example.com

Answer 2

Postfix doesn't permit to send email to a destination SMTP server that have the same myhostname in SMTP banner. Then you must set current myhostname to backup.example.org or something else.

myhostname is a machine name, to avoid this problem you could set the MX server name to 'dexter.example.org' and the backup server name to 'deedee.example.org'. RFC 1178 says 'Use theme names'.

Answer 3

I've found a work around by creating a new domain on the nameserver: "botmaster.corp.flatturtle.com".

The MX records point to another SMTP server.

Thus mailing root (which adds the @botmaster.corp.flatturtle.com domain) is forwarded and correctly delivered.