Download your favorite Linux distribution at LQ ISO.
Go Back > Forums > Linux Forums > Linux - Software
User Name
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.


  Search this Thread
Old 10-29-2006, 06:48 PM   #1
LQ Newbie
Registered: Oct 2006
Distribution: CentOS 4.4
Posts: 3

Rep: Reputation: 0
Exclamation Basic Postfix Installation Problem

I have posted my issue in numerous forums to no avail...PLEASE, I AM BEGGING YOU...HELP!

Setting up my test email server and have run into a snag: I can not connect to Postfix in any way (Outlook or telnet) from any other PC on my network. I am looking to replace my current Exchange 2000 server with my Linux as my primary email server so I need it to be able to receive email from the internet. (External MX record already configured)

I can:

- Ping my new Server
- Connect to the internet from my new server
- Telnet to Dovecot on the new server from another PC on my netwok through port 110.
- Send mail externally FROM my new server
- Telnet to Postfix FROM the server itself

I honestly believe this is a configuration issue within Postfix as I have disabled ALL firewalls, SELinux and IPTables to no avail. I just don't know where to begin..

Everything is a standard install except for what I have changed as listed below.
Here is what I have tried:

1) Installed CentOS 4.4. Install went fine. Selected a standard "server" config and only selected "Mail Server" additional to the standard server config during the initial install. Installed all updates and patches.
2) Installed Postfix via yum. Install went fine. ran the following:

# chkconfig --level 35 sendmail off
# chkconfig --level 35 postfix on
# /etc/rc.d/init.d/sendmail stop
# /etc/rc.d/init.d/postfix start

Configured only the following parameters in the file:

myhostname =
mydomain =
myorigin = $mydomain
mydestination = $myhostname, localhost.$mydomain, $mydomain
mail_spool_directory = /var/spool/mail
mynetworks =,

Ran system-switch-mail and selected Postfix as my MTA.

I completely disabled the firewall, SELinux, iptables service and rebooted.

Still couldn't connect to Postfix via telnet from my other machine OR any MUA
Old 10-29-2006, 07:42 PM   #2
Senior Member
Registered: Dec 2003
Location: phnom penh
Distribution: Fedora
Posts: 1,625

Rep: Reputation: 165Reputation: 165
Sounds like postfix is listening only on the loopback interface. In, you should have:
inet_interfaces = all
If that doesn't fix the problem, post the output of
postconf -n
Old 10-29-2006, 10:16 PM   #3
Registered: Oct 2005
Distribution: Slackware
Posts: 228

Rep: Reputation: 40
I agree that Postfix may only be listening on the loopback interface.

To check, run the following commands (and post the output for us to see):
netstat -pantu|grep -w 25
lsof -i :25
I would try the suggestion(s) offered by the previous user.

If it doesn't work, tell us whether you're connecting to your postfix server via it's hostname of ip address.

Another thing to try is to run tcpdump to see if any TCP/25 packets are hitting the postfix box from your LAN.
You can do that as follows (assuming you LAN is on eth1):
tcpdump -i eth1 port 25 -A
Old 10-30-2006, 12:20 AM   #4
LQ Newbie
Registered: Oct 2006
Distribution: CentOS 4.4
Posts: 3

Original Poster
Rep: Reputation: 0
Sorry -

That is exactly what I figgured out. I should have reposted my problem was solved...

Apparently Postfix is now shipping with it listening on the loopback..or at least from the CentOS yum repos...

Thanks for your patience and time!


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 send mail problem(In RH9, kernal 2.4.20, postfix 2.1.5) minor Linux - General 4 07-11-2005 10:12 PM
basic config for postfix dienerk Linux - General 1 10-25-2004 03:52 AM
basic installation human Linux - Newbie 5 10-05-2004 06:06 PM
Postfix basic configuration Swift&Smart Linux - Software 21 09-05-2004 06:38 PM
postfix server installation, samba server problem eozdoganci Linux - Networking 0 06-04-2004 07:14 AM > Forums > Linux Forums > Linux - Software

All times are GMT -5. The time now is 05:47 PM.

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