Set up Autodiscover for SmarterMail

What is autodiscover? Simply put, it allows email clients to automatically determine the mail server address and port simply from the user's email address and password. This greatly simplifies the setup process for new users or for setting up devices such as the iPhone, iPad or Android and Windows Phone devices.

Applies to SmarterMail 10.x - 15.x

To set up autodiscover for use with SmarterMail you will need to do the following:

  1. Create an A Record in your DNS
  2. Create a SRV Record in your DNS
  3. Create an IIS binding for autodiscover on your SmarterMail server

At the end of the article, we've listed what you can expect to be returned by a few devices and email clients once autodiscover is set up and working.

Creating an A Record

For autodiscover to work, you should create an A record for "autodiscover.your_domain.ext" that points to the IP address of your mail server. In the case of SmarterTools, we set up an A record for "" that points to the IP address of our mail server ( In our DNS, the line in our zone file for this A record looks like this:

autodiscover IN A

NOTE: There are many ways to manage DNS for a domain, as well as many DNS services that can be used, so providing step-by-step instructions is difficult. However, adding a record should be fairly straightforward. If you have questions, contact your IT professional or hosting provider for assistance.

Set up a SRV record in DNS

NOTE: To utilize autodiscover for e-mail clients, SmarterMail must be configured in IIS (NOT the default web server) and be listening over HTTPS. Therefore, port 443 MUST be available and not blocked by a firewall.

Next, you'll want to create a SRV record for your domain. This SRV record will return the available domain and service (SMTP, POP or IMAP) to the e-mail client querying for auto discovery. Technically, setting up a SRV record is an optional step when setting up autodiscover, but it is highly recommended as a backup to ensure autodiscover works properly.

The SRV record that is created should be in the following format: "_autodiscover._tcp.(your domain)" and return the root URL of your email server. Please check with your DNS provider for instructions on configuring an SRV record for your environment.

The following is an example details the SRV for SmarterTools:

Service: _Autodiscover
Protocol: _tcp
Priority: 0
Weight: 0
Port: 443

Verifying the SRV via NSLookup

To verify that you have set up the SRV record correctly, on a Windows machine open a command prompt and do the following:

  1. Type NSLOOKUP and press ENTER
  2. Type set type=srv and press ENTER
  3. Type, where "" is the name of your domain, and press ENTER

You should get something back that looks like this. NOTE: IPs and server URLs will match what you have set up for your mail server:

    Server: UnKnown

    Non-authoritative answer: SRV service location:
    priority = 0
    weight = 0
    port = 443
    svr hostname = internet address =

Create a Host Header (IIS Binding) for Autodiscover

A binding for autodiscover should be added to your SmarterMail website in IIS that points your autodiscover A record to your SmarterMail installation. Again, to use SmarterTools as an example, we have an IIS binding that binds port 80 and 443 to "" This is added in addition to the IIS binding for "" as the "" URL is what we use for setting up our email clients and for access to the Web interface.

From here, you should be able to open Outlook (or other desktop or mobile email client) and simply add the full email address and password and SmarterMail will take care of the rest.

Protocols Returned by Autodiscover

Not all devices and email clients handle autodiscover in the same way. Below is a list of devices and email clients and the protocols they return when seeking autdiscover settings from a mail server. This will help set expectations for users when setting up accounts using these clients.

  • Mobile devices (iOS, Android, Windows) will only return Exchange ActiveSync
  • Outlook 2007 and above will return IMAP
  • Windows 8 mail client will return Exchange ActiveSync
  • Thunderbird 3.0 and earlier does not support autodiscover but will try best effort to connect to any mail server

Applies to SmarterMail 8.x - 9.x

This feature is not available in these versions.


Learn more about SmarterMail's enterprise email features and benefits.


Thunderbird does support autodiscover:

Michael Muller (3/9/2018 at 2:10 PM)
Thanks for the link, Michael. The KB was updated to note Thunderbird 3.0 and earlier since 3.1 does support autodiscover.
Derek Curtis (3/14/2018 at 10:50 AM)