When should I use this master.cf?
Use it to restore a missing default, confirm what shipped, or diff against your current Postfix config.
#
# Postfix master process configuration file. For details on the format
# of the file, see the master(5) manual page (command: "man 5 master" or
# on-line: http://www.postfix.org/master.5.html).
#
# Do not forget to execute "postfix reload" after editing this file.
#
# ==========================================================================
# service type private unpriv chroot wakeup maxproc command + args
# (yes) (yes) (no) (never) (100)
# ==========================================================================
smtp inet n - y - - smtpd
#smtp inet n - y - 1 postscreen
#smtpd pass - - y - - smtpd
#dnsblog unix - - y - 0 dnsblog
#tlsproxy unix - - y - 0 tlsproxy
# Choose one: enable submission for loopback clients only, or for any client.
#127.0.0.1:submission inet n - y - - smtpd
#submission inet n - y - - smtpd
# -o syslog_name=postfix/submission
# -o smtpd_tls_security_level=encrypt
# -o smtpd_sasl_auth_enable=yes
# -o smtpd_tls_auth_only=yes
# -o smtpd_reject_unlisted_recipient=no
# Instead of specifying complex smtpd_<xxx>_restrictions here,
# specify "smtpd_<xxx>_restrictions=$mua_<xxx>_restrictions"
# here, and specify mua_<xxx>_restrictions in main.cf (where
# "<xxx>" is "client", "helo", "sender", "relay", or "recipient").
# -o smtpd_client_restrictions=
# -o smtpd_helo_restrictions=
# -o smtpd_sender_restrictions=
# -o smtpd_relay_restrictions=
# -o smtpd_recipient_restrictions=permit_sasl_authenticated,reject
# -o milter_macro_daemon_name=ORIGINATING
# Choose one: enable submissions for loopback clients only, or for any client.
#127.0.0.1:submissions inet n - y - - smtpd
#submissions inet n - y - - smtpd
# -o syslog_name=postfix/submissions
# -o smtpd_tls_wrappermode=yes
# -o smtpd_sasl_auth_enable=yes
# -o smtpd_reject_unlisted_recipient=no
# Instead of specifying complex smtpd_<xxx>_restrictions here,
# specify "smtpd_<xxx>_restrictions=$mua_<xxx>_restrictions"
# here, and specify mua_<xxx>_restrictions in main.cf (where
# "<xxx>" is "client", "helo", "sender", "relay", or "recipient").
# -o smtpd_client_restrictions=
# -o smtpd_helo_restrictions=
# -o smtpd_sender_restrictions=
# -o smtpd_relay_restrictions=
# -o smtpd_recipient_restrictions=permit_sasl_authenticated,reject
# -o milter_macro_daemon_name=ORIGINATING
#628 inet n - y - - qmqpd
pickup unix n - y 60 1 pickup
cleanup unix n - y - 0 cleanup
qmgr unix n - n 300 1 qmgr
#qmgr unix n - n 300 1 oqmgr
tlsmgr unix - - y 1000? 1 tlsmgr
rewrite unix - - y - - trivial-rewrite
bounce unix - - y - 0 bounce
defer unix - - y - 0 bounce
trace unix - - y - 0 bounce
verify unix - - y - 1 verify
flush unix n - y 1000? 0 flush
proxymap unix - - n - - proxymap
proxywrite unix - - n - 1 proxymap
smtp unix - - y - - smtp
relay unix - - y - - smtp
-o syslog_name=postfix/$service_name
# -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq unix n - y - - showq
error unix - - y - - error
retry unix - - y - - error
discard unix - - y - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - y - - lmtp
anvil unix - - y - 1 anvil
scache unix - - y - 1 scache
postlog unix-dgram n - n - 1 postlogd
#
# ====================================================================
# Interfaces to non-Postfix software. Be sure to examine the manual
# pages of the non-Postfix software to find out what options it wants.
#
# Many of the following services use the Postfix pipe(8) delivery
# agent. See the pipe(8) man page for information about ${recipient}
# and other message envelope options.
# ====================================================================
#
# maildrop. See the Postfix MAILDROP_README file for details.
# Also specify in main.cf: maildrop_destination_recipient_limit=1
#
maildrop unix - n n - - pipe
flags=DRXhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
#
# ====================================================================
#
# Recent Cyrus versions can use the existing "lmtp" master.cf entry.
#
# Specify in cyrus.conf:
# lmtp cmd="lmtpd -a" listen="localhost:lmtp" proto=tcp4
#
# Specify in main.cf one or more of the following:
# mailbox_transport = lmtp:inet:localhost
# virtual_transport = lmtp:inet:localhost
#
# ====================================================================
#
# Cyrus 2.1.5 (Amos Gouaux)
# Also specify in main.cf: cyrus_destination_recipient_limit=1
#
#cyrus unix - n n - - pipe
# flags=DRX user=cyrus argv=/cyrus/bin/deliver -e -r ${sender} -m ${extension} ${user}
#
# ====================================================================
# Old example of delivery via Cyrus.
#
#old-cyrus unix - n n - - pipe
# flags=R user=cyrus argv=/cyrus/bin/deliver -e -m ${extension} ${user}
#
# ====================================================================
#
# See the Postfix UUCP_README file for configuration details.
#
uucp unix - n n - - pipe
flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
#
# Other external delivery methods.
#
ifmail unix - n n - - pipe
flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp unix - n n - - pipe
flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix - n n - 2 pipe
flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman unix - n n - - pipe
flags=FRX user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py ${nexthop} ${user}
curl https://exampleconfig.com/api/v1/config/original/9eab02e958ed651f812e9e8f670e8b61?hint=master.cf
wget -O master.cf https://exampleconfig.com/api/v1/config/original/9eab02e958ed651f812e9e8f670e8b61?hint=master.cf
<prompt><role>DevOps agent</role><source url='https://exampleconfig.com/api/v1/config/original/9eab02e958ed651f812e9e8f670e8b61?hint=master.cf' /><config><app>Postfix</app><os>Debian 12 (Bookworm)</os><location>/etc/postfix/master.cf</location><lines>137</lines><md5>9eab02e958ed651f812e9e8f670e8b61</md5><sha256>dc0c1e54caed31a257573f8c29e77d2e13cc8608a41e8050fcb1e6bd7ee9deb1</sha256></config></prompt>
Paste into Claude, ChatGPT, or any AI assistant.
sudo apk add postfix
sudo apt update && sudo apt install postfix
sudo yum install postfix
sudo apt update && sudo apt install postfix
When should I use this master.cf?
Use it to restore a missing default, confirm what shipped, or diff against your current Postfix config.
How do I restore Postfix defaults?
Download the file, back up the current one in /etc/postfix/master.cf, replace it, then reload or restart Postfix.
Is master.cf safe for production?
It is the vendor default for Debian 12 (Bookworm). Treat it as a baseline and review security and performance settings before production use.
How does this differ from other OS versions?
Defaults vary by distro and version. This copy matches Debian 12 (Bookworm).
Can I use this for Postfix troubleshooting?
Yes. Diff it against yours to find drift, then restore only the sections you need.