postfix fails to send mail with "fatal: unknown service: smtp/tcp"

user3761616 asked:

I have installed postfix, and when I tried to send a mail to gmail it told me that it has been sent, but when I checked my inbox in Gmail I didn’t saw it.

This is how the connection looked like:

$ telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 DarkSenic ESMTP Postfix (Debian/GNU)
HELO localhost.localdomain
250 DarkSenic
MAIL FROM:<test@test.com>
250 2.1.0 Ok
RCPT TO:<mymail@gmail.com>
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Subject: Test

test
.
250 2.0.0 Ok: queued as E15692031E9
QUIT
221 2.0.0 Bye
Connection closed by foreign host.

And this is my main.cf file:

# 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 (Debian/GNU)
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 = DarkSenic
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = localhost.localdomain, DarkSenic, localhost.localdomain, localhost
relayhost = 
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 [2001:db8:1407:c3a0::]/60 128.66.85.168 10.0.0.0/24
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all

This is what I get in the log file:

Dec 28 18:48:23 DarkSenic postfix/smtpd[4623]: connect from unknown[::1]
Dec 28 18:49:18 DarkSenic postfix/smtpd[4623]: B2C422031EA: client=unknown[::1]
Dec 28 18:49:28 DarkSenic postfix/cleanup[5564]: B2C422031EA: message-id=<20141228164918.B2C422031EA@DarkSenic>
Dec 28 18:49:28 DarkSenic postfix/qmgr[16196]: B2C422031EA: from=<test@test.com>, size=322, nrcpt=1 (queue active)
Dec 28 18:49:28 DarkSenic postfix/smtp[5565]: fatal: unknown service: smtp/tcp
Dec 28 18:49:29 DarkSenic postfix/qmgr[16196]: warning: private/smtp socket: malformed response
Dec 28 18:49:29 DarkSenic postfix/qmgr[16196]: warning: transport smtp failure -- see a previous warning/fatal/panic logfile record for the problem description
Dec 28 18:49:29 DarkSenic postfix/master[29689]: warning: process /usr/lib/postfix/smtp pid 5565 exit status 1
Dec 28 18:49:29 DarkSenic postfix/master[29689]: warning: /usr/lib/postfix/smtp: bad command startup -- throttling
Dec 28 18:49:29 DarkSenic postfix/error[5566]: B2C422031EA: to=<myemail@gmail.com>, relay=none, delay=41, delays=40/1/0/0.05, dsn=4.3.0, status=deferred (unknown mail transport error)
Dec 28 18:49:30 DarkSenic postfix/smtpd[4623]: disconnect from unknown[::1]

grep smtp /etc/services gives me:

smtp        25/tcp      mail
ssmtp       465/tcp     smtps       # SMTP over SSL

This is what I have in my master.cf file:

#
# Postfix master process configuration file.  For details on the format
# of the file, see the master(5) manual page (command: "man 5 master").
#
# Do not forget to execute "postfix reload" after editing this file.
#
# ==========================================================================
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
# ==========================================================================
smtp      inet  n       -       -       -       -       smtpd
#smtp      inet  n       -       -       -       1       postscreen
#smtpd     pass  -       -       -       -       -       smtpd
#dnsblog   unix  -       -       -       -       0       dnsblog
#tlsproxy  unix  -       -       -       -       0       tlsproxy
#submission inet n       -       -       -       -       smtpd
#  -o syslog_name=postfix/submission
#  -o smtpd_tls_security_level=encrypt
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#smtps     inet  n       -       -       -       -       smtpd
#  -o syslog_name=postfix/smtps
#  -o smtpd_tls_wrappermode=yes
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_client_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#628       inet  n       -       -       -       -       qmqpd
pickup    fifo  n       -       -       60      1       pickup
cleanup   unix  n       -       -       -       0       cleanup
qmgr      fifo  n       -       n       300     1       qmgr
#qmgr     fifo  n       -       n       300     1       oqmgr
tlsmgr    unix  -       -       -       1000?   1       tlsmgr
rewrite   unix  -       -       -       -       -       trivial-rewrite
bounce    unix  -       -       -       -       0       bounce
defer     unix  -       -       -       -       0       bounce
trace     unix  -       -       -       -       0       bounce
verify    unix  -       -       -       -       1       verify
flush     unix  n       -       -       1000?   0       flush
proxymap  unix  -       -       n       -       -       proxymap
proxywrite unix -       -       n       -       1       proxymap
smtp      unix  -       -       -       -       -       smtp
relay     unix  -       -       -       -       -       smtp
#       -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq     unix  n       -       -       -       -       showq
error     unix  -       -       -       -       -       error
retry     unix  -       -       -       -       -       error
discard   unix  -       -       -       -       -       discard
local     unix  -       n       n       -       -       local
virtual   unix  -       n       n       -       -       virtual
lmtp      unix  -       -       -       -       -       lmtp
anvil     unix  -       -       -       -       1       anvil
scache    unix  -       -       -       -       1       scache
#
# ====================================================================
# 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=DRhu 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
#  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=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
  ${nexthop} ${user}

Why doesn’t it work? and how can I fix it?
I found some answers on the internet but they didn’t work for me…

Thank you for reading and have a nice day 🙂

My answer:


On Debian, postfix doesn’t read /etc/services, but expects these files to exist in the queue_directory (usually /var/spool/postfix). So it is actually trying to read /var/spool/postfix/etc/services, which either doesn’t exist or is corrupted.

Try recreating this file, or better yet just link it (if you aren’t running postfix in a chroot).

sudo ln -snf /etc/services /var/spool/postfix/etc/services

If you are chrooting postfix, copy the file instead.

sudo cp -f /etc/services /var/spool/postfix/etc/services

View the full question and answer on Server Fault.

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.