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Why is Postfix throwing "malformed response" and "bad command startup" errors when I send mail?

When sending an email from my server like:

mail -s testing email@example.tld
this is a test

EOT

I get this in /var/log/maillog:

Aug  6 09:46:23 serverhostname postfix/pickup[1703]: B7684140C31: uid=0 from=<root>
Aug  6 09:46:23 serverhostname postfix/cleanup[1854]: B7684140C31: message-id=<20150806164623.B7684140C31@serverhostname>
Aug  6 09:46:23 serverhostname postfix/qmgr[1704]: B7684140C31: from=<root@serverhostname>, size=441, nrcpt=1 (queue active)
Aug  6 09:46:23 serverhostname postfix/smtp[1856]: fatal: unknown service: smtp/tcp
Aug  6 09:46:24 serverhostname postfix/qmgr[1704]: warning: private/smtp socket: malformed response
Aug  6 09:46:24 serverhostname postfix/qmgr[1704]: warning: transport smtp failure -- see a previous warning/fatal/panic logfile record for the problem description
Aug  6 09:46:24 serverhostname postfix/master[1701]: warning: process /usr/libexec/postfix/smtp pid 1856 exit status 1
Aug  6 09:46:24 serverhostname postfix/master[1701]: warning: /usr/libexec/postfix/smtp: bad command startup -- throttling
Aug  6 09:46:24 serverhostname postfix/error[1857]: B7684140C31: to=<email@example.tld>, relay=none, delay=1.1, delays=0.03/1/0/0.02, dsn=4.3.0, status=deferred (unknown mail transport error)

postconf -n gives me:

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
config_directory = /etc/postfix
inet_interfaces = loopback-only
inet_protocols = all
mailbox_size_limit = 0
message_size_limit = 40960000
mydestination = serverhostname, localhost.localdomain, localhost
myhostname = serverhostname
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
readme_directory = no
recipient_delimiter = +
relayhost = internal-relay-server
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes

/etc/postfix/master.cf looks like:

#
# 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)   (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_reject_unlisted_recipient=no
#  -o smtpd_client_restrictions=$mua_client_restrictions
#  -o smtpd_helo_restrictions=$mua_helo_restrictions
#  -o smtpd_sender_restrictions=$mua_sender_restrictions
#  -o smtpd_recipient_restrictions=
#  -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#smtps     inet  n       -       -       -       -       smtpd
#  -o syslog_name=postfix/smtps
#  -o smtpd_tls_wrappermode=yes
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_reject_unlisted_recipient=no
#  -o smtpd_client_restrictions=$mua_client_restrictions
#  -o smtpd_helo_restrictions=$mua_helo_restrictions
#  -o smtpd_sender_restrictions=$mua_sender_restrictions
#  -o smtpd_recipient_restrictions=
#  -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#628       inet  n       -       -       -       -       qmqpd
pickup    unix  n       -       -       60      1       pickup
cleanup   unix  n       -       -       -       0       cleanup
qmgr      unix  n       -       n       300     1       qmgr
#qmgr     unix  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}

Email is supposed to be relayed through an Ubuntu 14.04 server running postix as an internal only relay. It then relays the email to our Groupwise server.

That works on most of my servers, a quick check makes me think only my CentOS servers are having this issue.

The server I'm testing on is running CentOS 6.6.

I configured postfix to match what my Ubuntu servers have working.

I did copy the snakeoil certs referenced on my Ubuntu servers to where they are supposed to be on the CentOS server. It did not help.

Any suggestions?

Note: I apologize if the answer is obvious or a simple Google search would find the answer. I'm not feeling well, and only working on this because it's urgent. My Google searches have not turned up anything yet...

David R.
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  • thanks, that is almost a duplicate. I had ignored it earlier because this is centos, not debian. But I tried turning chroot off for smtp, and it started working. I tried the copy /etc/service solution, but it only partially worked. There's more stuff missing in the chroot environment. It can't find the relayserver. So I'll work on that now. – David R. Aug 06 '15 at 22:54

0 Answers0