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So I can't seem to access smtp from externally. When using a desktop email client (eM client and thunderbird both fail) I can't get it to hit the server at all. (eM client is trying to hit: smtp://xxx@mail.xxxxxx.com:25 if that helps)

I looked through nmap and it looks like port 25 is open for everyone.

Also, I tried telnet from another server and I got the following error:

554 5.7.1 <xxxxx@gmail.com>: Relay access denied

Here is my postconf -n:

alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
config_directory = /etc/postfix
delay_warning_time = 4h
disable_vrfy_command = yes
inet_interfaces = all
local_recipient_maps =
maximal_backoff_time = 8000s
maximal_queue_lifetime = 7d
message_size_limit = 30720000
minimal_backoff_time = 1000s
mydestination =
mynetworks = 127.0.0.0/8
myorigin = /etc/mailname
readme_directory = /usr/share/doc/postfix
relayhost =
smtp_helo_timeout = 60s
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name
smtpd_client_restrictions = reject_rbl_client sbl.spamhaus.org, reject_rbl_client blackholes.easynet.nl, reject_rbl_client dnsbl.njabl.org
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_delay_reject = yes
smtpd_hard_error_limit = 12
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, warn_if_reject reject_non_fqdn_hostname, reject_invalid_hostname, permit
smtpd_recipient_limit = 16
smtpd_recipient_restrictions = reject_unauth_pipelining, permit_mynetworks, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_unauth_destination, permit
smtpd_sender_restrictions = permit_mynetworks, warn_if_reject reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unauth_pipelining, permit
smtpd_soft_error_limit = 3
smtpd_tls_cert_file = /etc/postfix/smtpd.cert
smtpd_tls_key_file = /etc/postfix/smtpd.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
unknown_local_recipient_reject_code = 450
virtual_alias_maps = mysql:/etc/postfix/mysql_alias.cf
virtual_gid_maps = static:5000
virtual_mailbox_base = /var/spool/mail/vmail
virtual_mailbox_domains = mysql:/etc/postfix/mysql_domains.cf
virtual_mailbox_maps = mysql:/etc/postfix/mysql_mailbox.cf
virtual_uid_maps = static:5000

Here 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
#myorigin=xxxx.com

# This is already done in /etc/mailname
#myhostname = xxxx.xxxx.com

smtpd_banner = $myhostname ESMTP $mail_name
#biff = no


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

readme_directory = /usr/share/doc/postfix

# TLS parameters
smtpd_tls_cert_file = /etc/postfix/smtpd.cert
smtpd_tls_key_file = /etc/postfix/smtpd.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.

# Relay smtp through another server or leave blank to do it yourself
#relayhost = smtp.yourisp.com

# Network details; Accept connections from anywhere, and only trust this machine
mynetworks = 127.0.0.0/8
inet_interfaces = all
#mynetworks_style = host

# Masquerade emails aka convert username@mail.example.com to username@example.com
# !sub.domain.com means not to masquerade
#masquerade_domains = xxxx.com
#masquerade_exceptions = root

#As we will be using virtual domains, these need to be empty
local_recipient_maps =
mydestination =

# how long if undelivered before sending "delayed mail" warning update to sender
delay_warning_time = 4h
# will it be a permanent error or temporary
unknown_local_recipient_reject_code = 450
# how long to keep message on queue before return as failed.
# some have 3 days, I have 16 days as I am backup server for some people
# whom go on holiday with their server switched off.
maximal_queue_lifetime = 7d
# max and min time in seconds between retries if connection failed
minimal_backoff_time = 1000s
maximal_backoff_time = 8000s
# how long to wait when servers connect before receiving rest of data
smtp_helo_timeout = 60s
# how many address can be used in one message.
# effective stopper to mass spammers, accidental copy in whole address list
# but may restrict intentional mail shots.
smtpd_recipient_limit = 16
# how many error before back off.
smtpd_soft_error_limit = 3
# how many max errors before blocking it.
smtpd_hard_error_limit = 12


# Requirements for the HELO statement
smtpd_helo_restrictions = permit_mynetworks, warn_if_reject reject_non_fqdn_hostname, reject_invalid_hostname, permit
# Requirements for the sender details
smtpd_sender_restrictions = permit_mynetworks, warn_if_reject reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unauth_pipelining, permit
# Requirements for the connecting server
smtpd_client_restrictions = reject_rbl_client sbl.spamhaus.org, reject_rbl_client blackholes.easynet.nl, reject_rbl_client dnsbl.njabl.org
# Requirement for the recipient address
smtpd_recipient_restrictions = reject_unauth_pipelining, permit_mynetworks, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_unauth_destination, permit
smtpd_data_restrictions = reject_unauth_pipelining
# require proper helo at connections
smtpd_helo_required = yes
# waste spammers time before rejecting them
smtpd_delay_reject = yes
disable_vrfy_command = yes

# not sure of the difference of the next two
# but they are needed for local aliasing
alias_maps = hash:/etc/postfix/aliases
alias_database = hash:/etc/postfix/aliases
# this specifies where the virtual mailbox folders will be located
virtual_mailbox_base = /var/spool/mail/vmail
# this is for the mailbox location for each user
virtual_mailbox_maps = mysql:/etc/postfix/mysql_mailbox.cf
# and this is for aliases
virtual_alias_maps = mysql:/etc/postfix/mysql_alias.cf
# and this is for domain lookups
virtual_mailbox_domains = mysql:/etc/postfix/mysql_domains.cf
# this is how to connect to the domains (all virtual, but the option is there)
# not used yet
# transport_maps = mysql:/etc/postfix/mysql_transport.cf

# Setup the uid/gid of the owner of the mail files - static:5000 allows virtual ones
virtual_uid_maps = static:5000
virtual_gid_maps = static:5000

#######################
## OLD CONFIGURATION ##
#######################
#myorigin = /etc/mailname
#mydestination = xxxx.xxxx.com, localhost, localhost.localdomain
#mailbox_size_limit = 0
#recipient_delimiter = +
#html_directory = /usr/share/doc/postfix/html
message_size_limit = 30720000
#virtual_alias_domains =
##virtual_alias_maps = hash:/etc/postfix/virtual
#virtual_mailbox_base = /home/vmail
##luser_relay = webmaster
#smtpd_sasl_type = dovecot
#smtpd_sasl_path = private/auth
#smtpd_sasl_auth_enable = yes
#smtpd_sasl_security_options = noanonymous
#broken_sasl_auth_clients = yes
#smtpd_sasl_authenticated_header = yes
#smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
#virtual_create_maildirsize = yes
#virtual_maildir_extended = yes
#proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $virtual_mailbox_limit_maps
#virtual_transport = dovecot
#dovecot_destination_recipient_limit = 1

Also, here is my master.cf

#
# 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
#submission inet n       -       -       -       -       smtpd
#  -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 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       -       -       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
# When relaying mail as backup MX, disable fallback_relay to avoid MX loops
relay     unix  -       -       -       -       -       smtp
        -o smtp_fallback_relay=
#       -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}
dovecot   unix  -       n       n       -       -       pipe
    flags=DRhu user=vmail:vmail argv=/usr/lib/dovecot/deliver -d ${recipient}

I used to have dovecot, but have switched over to courier. Courier seems to be working properly (I'm able to imap correctly) but it's just SMTP that is failing. And the weird part is I can send an SMTP email from the server itself through telnet, but it's only when I try to telnet into the server from another server or when I try and send an email through a desktop email client that it fails. (the desktop clients don't even register in syslog even though I have logging enabled through iptables)

I'm not that experienced with mail servers so I'm at a loss as to what to even ask. I tried altering some of the relay parameters in main.cf but nothing seemed to change things. Also, I still can't get my mail clients to properly even access my server for some reason even though it was working before when I had the params in place for dovecot (which have still been left in the main.cf but commented out)

tl;dr Why would I get a relay access denied when trying to send an email from an external server? Also, why would I not be able to access smtp through my desktop email clients?

Any additional information can be readily available as needed/requested

Thanks in advance.

Aram Papazian
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    I'm not 100% positive regarding this but it seems like you lack the `inet_protocols=all` in the `/etc/main.cf` file . – Itai Ganot Aug 05 '13 at 15:02

2 Answers2

3

Your SMTP service seems to be working fine.

Your problem is that you're trying to send email from your MUA on port 25, which is a bad idea even if you could make it work somehow.

You need to enable the submission section in your postfix master.cf and then configure your email client to send on port 587 instead of 25.

Michael Hampton
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  • Awesome! Thanks for all the information =) I was planning on doing some of that but didn't realize there was more to it. I'm able to hit the server properly now (well, minus that I'm getting SASL authentication isues, but that's a different story which I'm trying to figure out). Thanks a million! – Aram Papazian Aug 05 '13 at 15:54
1

If your desktop client is on a home network, there's an excellent chance that your ISP prohibits outbound connections on port 25. If your connection attempts are being blocked by your ISP that would explain why you see no evidence of them on your server.

As Michael Hampton says, you can enable the submission service on port 587. I would also recommend setting up SSL and, ideally, authentication for outbound mail.

Regarding the relaying error: you have not set smtpd_relay_restrictions in your configuration, which means you're using the default value of permit_mynetworks, permit_sasl_authenticated, defer_unauth_destination. This means that unless you're authenticating to your server with a username and password, Postfix will reject email unless:

  • The client IP address matches any network or network address listed in $mynetworks.
  • Postfix is mail forwarder: the resolved RCPT TO domain matches $relay_domains or a subdomain thereof, and contains no sender-specified routing (user@elsewhere@domain),
  • Postfix is the final destination: the resolved RCPT TO domain matches $mydestination, $inet_interfaces, $proxy_interfaces, $virtual_alias_domains, or $virtual_mailbox_domains, and contains no sender-specified routing (user@elsewhere@domain).

This is from: http://www.postfix.org/SMTPD_ACCESS_README.html (and related configuration documentation).

larsks
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