Latest LQ Deal: Complete CCNA, CCNP & Red Hat Certification Training Bundle
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 06-05-2012, 02:27 PM   #1
Registered: Jan 2009
Posts: 35

Rep: Reputation: 0
Cant connect to outgoing SMTP server. Tried almost everything.

Ubuntu 10.04

MTA is receiving mail just fine. Though when I try to send a message with Thunderbird or MacMail it just hangs and times out.

I am on a business cable connection and my ISP doesn't block the popular ports. I've tried everything I can think of in the router as far as Firewall and routing issues. I've confirmed that port 465 is open and listening for SSL/TLS connections. I've tried every possible combination in the outgoing server settings of TB...

When I switch to my ISP's outgoing smtp settings (port 25) the messages fly out the door. But that essentially means I'm bypassing my server.. Not really what I wanted to do.

Thanks to anyone who can help.
Old 06-05-2012, 02:48 PM   #2
Registered: Jan 2009
Posts: 35

Original Poster
Rep: Reputation: 0
Now it seems that my Mac has figured out how to send through the server. So it is beginning to look like a Thunderbird issue. Still frustrating. One problem is that the Mac doesn't appear to be using a secure login to send.

Last edited by mwx; 06-05-2012 at 03:29 PM.
Old 06-05-2012, 05:03 PM   #3
Registered: Jan 2009
Posts: 35

Original Poster
Rep: Reputation: 0
After further testing - I have the same problem with just about every mail client (Mac Mail, Thunderbird, Windoze Live) - essentially - none of them can authenticate over SSL/TLS for outgoing mail. However - all of them work when you try to send an unsecured mail through port 25 (relay).

Thunderbird: Authentication Method: Password, transmitted insecurely - Connection Security: None
Windoze Live Mail: Outgoing Port 25, Server requires authentication, seems to authenticate via plain-text and works with username and password. I selected "This server requires a secure connection (SSL)" over port 25 and the mail went right through without complaint. So who knows. When I switched the port back over to 465 I get the following:
"Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity.

Subject 'this is the result of setting the SSL port to 465'
Server: '**********.com'
Windows Live Mail Error ID: 0x800CCC0F
Protocol: SMTP
Port: 465
Secure(SSL): Yes"

As for Apple Mail - it won't even get by the self-signed cert..
Old 06-06-2012, 09:07 AM   #4
Registered: Jan 2009
Posts: 35

Original Poster
Rep: Reputation: 0
As it turns out - there were many issues that I chipped away at and it boiled down to this:
Using this article as a guide - which is excellent, but leaves a few things out. I managed to get everything up and running - but couldn't connect via port 465. What the guide doesn't tell you (what I only found through searching for the answer) is that you must go and un-comment the following in your /etc/postfix/ I guess the guide's author assumes you know to do it..

smtps inet n - - - - smtpd
-o smtpd_tls_wrappermode=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_sasl_authenticated,reject

I had un-commented the second two lines in the beginning - but not the first.
This in combination with some port forwarding to 465 in the router was the solution to getting all of the other mail clients to connect to the outgoing SMTP server. I still have yet to test the Apple Mail.
Old 06-06-2012, 02:56 PM   #5
Senior Member
Registered: Jul 2007
Distribution: Ubuntu 10.10, Slackware 64-current
Posts: 2,124

Rep: Reputation: 778Reputation: 778Reputation: 778Reputation: 778Reputation: 778Reputation: 778Reputation: 778
As a point of reference, there is also a confusion factor associated with a legacy standard of email using SSL (secure SMTP) on port 465. The modern method is to use encryption on email over port 25. There is also an additional confusion factor associated with SSL/TLS versus STARTTLS.

This Wikipedia article should help clarify some of these issues for you.


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
Unable to connect to outgoing SMTP server audiodef Linux - Server 3 07-13-2011 09:08 AM
forward outgoing smtp traffic from linux mail server to window machine using iptables r.bhange Linux - Networking 2 06-04-2009 12:39 AM
kmail - cannot connect to smtp server. emeskay Linux - Software 8 11-10-2004 10:34 PM
How to implement a SMTP server for outgoing mail? Nerox Programming 1 07-02-2004 03:43 AM
Can't connect to RedHat 9 SMTP server from XP bper Linux - Networking 1 10-22-2003 09:07 AM > Forums > Linux Forums > Linux - Server

All times are GMT -5. The time now is 02:24 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