Download your favorite Linux distribution at LQ ISO.
Go Back > Forums > Linux Forums > Linux - Server
User Name
Linux - Server This forum is for the discussion of Linux Software used in a server related context.


  Search this Thread
Old 05-14-2013, 09:53 AM   #1
Registered: Dec 2012
Location: Southampton, UK
Posts: 36

Rep: Reputation: Disabled
Post [Postfix] 450 Sender address rejected: Domain not found

I am about to migrate my mail system onto another machine. I copied everything there and this is what I started getting when I wanted to send a test mail from gmail -> my server.

May 14 15:33:18 mailserver postfix/smtpd[1688]: connect from unknown[]
May 14 15:33:19 mailserver postfix/smtpd[1688]: NOQUEUE: reject: RCPT from unknown[]: 450 4.1.8 <>: Sender address rejected: Domain not found; from=<> to=<> proto=ESMTP helo=<>
May 14 15:33:19 mailserver postfix/smtpd[1688]: disconnect from unknown[]
From the official postfix documentation I read that 450 code is mostly a temporary DNS error. Strange, as when I do
dig all
host -t mx
- everything is being resolved correctly. Below, I posted my, although the configuration is OK (as I have it on another server which is now online and accepting everything correctly). My intention is not to remove the restrictions which cause the problem for that won't resolve them. I would like to find out what causes such a behaviour? How postfix checks other domains' MX entries? Thanks for any tips in advance.

Please find the below:

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
body_checks =
broken_sasl_auth_clients = yes
config_directory = /etc/postfix
header_checks =
inet_interfaces = all
mail_spool_directory = /maildirs/$USER/
mailbox_size_limit = 0
message_size_limit = 220240000
mydestination = $myhostname, /etc/postfix/virtual/domains, localhost
mydomain =
myhostname =
mynetworks = ...
myorigin = /etc/mailname
readme_directory = no
receive_override_options = no_address_mappings
recipient_delimiter = +
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = MAIL SERVER
smtpd_client_restrictions =
smtpd_helo_required = yes
smtpd_helo_restrictions = reject_unauth_pipelining, reject_invalid_helo_hostname, permit
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_unauth_destination, reject_unknown_sender_domain, permit
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, check_sender_access hash:/etc/postfix/sender_access reject_unknown_sender_domain, reject_non_fqdn_sender, reject_unauth_destination, permit
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
unknown_hostname_reject_code = 550
Old 05-15-2013, 04:56 AM   #2
Registered: Nov 2004
Location: Russia (St.Petersburg)
Distribution: Debian
Posts: 666

Rep: Reputation: 68
check_sender_access hash:/etc/postfix/sender_access reject_unknown_sender_domain
if in the list?
Old 05-16-2013, 04:19 PM   #3
Registered: Dec 2012
Location: Southampton, UK
Posts: 36

Original Poster
Rep: Reputation: Disabled
No, it's not. Maybe it is because I've got just 2 ports opened, 25 and 143?

More weird messages are coming though (I'm trying to send mails to gmail):

May 16 22:17:30 mail postfix/smtp[3835]: 1AB5EE07FF: to=<>,
 relay=none, delay=382, delays=382/0.02/0/0, dsn=4.4.3, status=deferred (Host or domain name not found. 
Name service error for type=MX: Host not found, try again)
however I can do dig easily, and everything else!
Old 05-16-2013, 04:51 PM   #4
Registered: Dec 2012
Location: Southampton, UK
Posts: 36

Original Poster
Rep: Reputation: Disabled

Ok, I have been digging and digging and here's what I found. By the occation thank you other linuxquestioners for helping in resolving issues!

I've just found this thread:

The link when you go there, says that apparently my postfix was chrooted and I needed to copy resolv.conf and services to /var/spool/postfix. Now why I used the expression "was chrooted". It is because I did not indicate a chroot installation of postfix. All I did on the new server was yum -y install postfix.

Now knowing that, and having gained some experience I would like to ask you how can I distinguish between a chrooted installation and a regular installation of postfix. Moreover, is that now a standard in Centos? I do not mind security at all, but would be nice to know what is getting installed on your system by default!

Last edited by pestka; 05-16-2013 at 04:52 PM.
Old 05-17-2013, 01:35 AM   #5
Registered: Nov 2004
Location: Russia (St.Petersburg)
Distribution: Debian
Posts: 666

Rep: Reputation: 68
I still do not understand, why the comma is missed between check_sender_access and reject_unknown_sender_domain.
To check if the running process is chrooted you can look at the /proc/<PID>/root symlink


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Postfix + Recipient address rejected: def1 Linux - Server 2 12-09-2012 01:02 AM
[SOLVED] [Postfix] Sender address rejected: Domain not found WojtekO Linux - Networking 5 05-19-2011 11:40 AM
Postfix: Sender address rejected when matching $mydestination [GOD]Anck Linux - Software 1 02-16-2005 06:42 AM
Sendmail: Domain of sender address does not exist 360 Linux - Networking 1 02-02-2003 09:40 PM
Sendmail Domain of sender address does not exist mantiev Linux - Networking 0 05-08-2001 08:58 AM > Forums > Linux Forums > Linux - Server

All times are GMT -5. The time now is 01:30 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration