Unable to Send Outbound Test Emails

Posted on 2008-09-30
Last Modified: 2012-05-05
I am performing final tests for outbound and inbound email with new Exchange 2007 Server via telnet.  Public DNS "MX" records still not pointing to this server for "live" email, I want to make sure everything works before I "flip the switch".

I can telnet into the Exchange Server remotely and locally.  Using the command line I can get the Exchange Server to accept an inbound email, and route it to my Mailbox - it works perfectly.

Outbound, however, is still not working.  When I try to send mail from my user account, and I put in the external email address I want the mail to go to, I get the 550.7.1 "Unable to relay" message.  I thought I had all the proper settings in my connectors, but here's what I have:

1) In the Organization config, under Hub Transport, in Send Connectors, I created one called "Send to Internet"... on the Network tab of the properties I have checked: "Use DNS "MX" records to route mail automatically" and at the bottom I have also checked: "Use external DNS Lookup settings on Transport server"

2) In the Server config, under Hub Transport, in the top pane SMTP properties, on the External DNS Lookups tab, I have checked: "Use these DNS servers" and I have entered the IP address of a server that is authorized for me to use by my Web Hosting company.

What else am I missing?  Why won't outbound email go out?

Thanks for all help.
Question by:Rob Grinage
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LVL 40

Expert Comment

ID: 22608770
Hello spock9458,

From what I understand, there are 2 ways to get email sent.

1 - Open Relay

This tells your server that email bound for somewhere else can be relayed to the public SMTP server of the recipient's domain. This is normally disabled on newer systems as it is a potential security hazard.

2 - Secured SMTP and / or authentication

This forces you to authenticate yourself to the server so that the relay can take place.

Look at the AUTH command for SMTP via telnet.



Author Comment

by:Rob Grinage
ID: 22609118
RQ -
If I understand this, the reason it might not be working is that I am not "authentically" logged in to the Telnet session?  I understand, and am researching online about how to authenticate.
However, now when I telnet in, I am typing EHLO which gives me the 250 Hello response.  Then when I type "auth login" I get an error:
504 5.7.4 Unrecognized authentication type
Am I missing a setting somewhere in EMC?
LVL 40

Expert Comment

ID: 22609244 discusses making sure authentication is enabled and working.

It isn't about using an authenticated connection to the SMTP server, it is about identifying yourself to whilst sending the SMTP message. You can use an unsecured connection.

Author Comment

by:Rob Grinage
ID: 22609605
I tried following the instructions in the link you suggested, but in the list of available commands after I type EHLO, it says AUTH NTLM, not AUTH PLAIN, or AUTH and PLAIN
So, if I'm connected simply by typing EHLO, then I type "mail from:" it says "Sender OK".  Then I type "rcpt" and it says "Unable to relay."  This means that I am not properly authenticated to send mail as through Telnet, right?
It may very well be, then, that when I begin to use the Exchange Server "live", and using my workstation and my Outlook program hooked up to my Exchange mailbox, which all operates within AD, I may be able to send outbound mail just fine?
I just wish there were a way to test for sure, I have a rather small (30 user) network, but if I go "live" and nobody is able to send emails outside our company, that is going to be a very bad thing - for me.
LVL 40

Accepted Solution

RQuadling earned 250 total points
ID: 22609645
Not through telnet. Through SMTP.

"It may very well be, then, that when I begin to use the Exchange Server "live", and using my workstation and my Outlook program hooked up to my Exchange mailbox, which all operates within AD, I may be able to send outbound mail just fine?"

Most likely.

Outlook doesn't use SMTP, it uses MAPI (or CDO, or Extended MAPI, never sure exactly which).

Also Outlook is authenticated by AD.

Why not just choose 1 user to use the other exchange server? Or create a new account and mailbox and use that as a test using Outlook?
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Author Comment

by:Rob Grinage
ID: 22609821
RQ -
Thanks for that, what a "DUH" moment for me.  But, in doing that I have discovered that there is a problem.  The outbound message is stuck in the queue, with the error of 451 4.4.0 DNS Query failed.  Is there any way to track down this new error quickly?  I thought I had everything set up correctly to Lookup DNS MX records through my Web Host server...
LVL 40

Expert Comment

ID: 22609869
Not that I can think of. I'm not 100% on top of Exchange. Sorry.

Author Closing Comment

by:Rob Grinage
ID: 31501707
You provided the solution for my initial question... therefore you deserve the points.  Now - on to the next "hurdle".
LVL 40

Expert Comment

ID: 22609948
Thank you. Sometimes it is going to be 1 hurdle per expert.

I'm settling down to watch Prison Break, so didn't want to leave you hanging.

Good luck.

Expert Comment

ID: 22615480
I am having the same issue as the person stated in the initial question.

I can send external email just fine with outlook but cannot use the command line to send an external email.

the reason we are testing this is because we have an application that needs to send mail to external users from time to time.  we get unable to relay errors when the application tries to send an email from an internal employee to any external address.

I was kind of foggy on what you were talking about in regards to creating another account and use it?

any help or suggestions?

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