We help IT Professionals succeed at work.

Off site clients connecting via IMAP on outlook cannot send mail to outside domains, error relaying not allowed.

Last Modified: 2013-11-30
Trying to setup exchange and smtp for users who will connect via outlook or mac mail to the exchange server with imap.  I can get the users logged in to recieve mail and sync folders but sending via smtp fails.  If I use no authentication the user can send mail to internal addresses but external addresses come back with no relay allowed.  If I try to setup outgoing mail server authentication on the clients they do not connect to the outgoing mail server, it keeps saying incorrect username or password.  I have tried every variation of domain\username, username, and username@domain I can think of.

This is a new installation of exchange 2003 on a SBS.
Watch Question

Jeffrey Kane - TechSoEasyPrincipal Consultant
Most Valuable Expert 2016
Top Expert 2014

External users with Outlook shouldn't be using IMAP, they should be using RPC over HTTPS.  This feature must be enabled in the Configure Email and Internet Connection Wizard (CEICW -- which is linked as Connect to the Internet in the Server Management Console > To-Do List) by checking the box on the Web Services Configuration Screen for "Outlook via the Internet".

A visual how-to is here:  http://sbsurl.com/ceicw

Port 443 must be open on your router/firewall.

Then RPC over HTTPS client configuration instructions are on the server's Remote Web Workplace main menu -- linked as "Configure Outlook via the Internet" -- access the RWW Main Menu by going to http://localhost/remote from on your server.  (See http://sbsurl.com/rww for more info on RWW).

A full overview for SBS based RPC/HTTPS configurations is here:  http://sbsurl.com/rpc

For Mac users, you might still want to use IMAP, but I'd suggest they use OWA instead.  If you insist on IMAP then you need to set their outgoing server to their ISP's and not allow relay through your SBS/Exchange server.



Sorry I was tying to take a shortcut on this.

When I say outlook, I am using outlook to test this.  The 2 users that will be connecting with thier laptops are on macs using mail, which I don't have to test with.  If I had a client using outlook I agree rpc would be the way to go.  

I can't set it up to use thier isp's smtp because they only allow connection to smtp if you are on thier network.  So I need to setup smtp on exchange.  I do not want an open relay so I would like some setup of authentication.
Jeffrey Kane - TechSoEasyPrincipal Consultant
Most Valuable Expert 2016
Top Expert 2014

That's why I suggest that they user OWA instead.  Since Mac Mail can't deal with Contacts and Calendar, it would make more sense to use OWA.



I agree with that as well but that answer does not work with my client.  He has 2 email accounts on his mac mail and doesn't want to use something different.  
Cloud/Infrastructure Solutions Architect
This one is on us!
(Get your first solution completely free - no credit card required)

Gain unlimited access to on-demand training courses with an Experts Exchange subscription.

Get Access
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Empower Your Career
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE

Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Unlock the solution to this question.
Join our community and discover your potential

Experts Exchange is the only place where you can interact directly with leading experts in the technology field. Become a member today and access the collective knowledge of thousands of technology experts.

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.