# iRedMail Easy: Setup DNS records for autoconfig and autodiscover

Attention

Check out the lightweight on-premises email archiving software developed by iRedMail team: Spider Email Archiver.

iRedMail Easy offers component `Autoconfig and Autodiscover` to help end users setup their MUA like Thunderbird and Outlook which supports autoconfig and autodiscover protocol.

This tutorial explains how autoconfig and autodiscover works, and how to setup required DNS records to get them working. In this tutorial, we use:

- `customer.com` is your customer's mail domain name.

- `mail.host.com` is the hostname of your mail server deployed with iRedMail Easy platform, it's public IPv4 address is `a.b.c.d`. IP can be either IPv4 or IPv6, we use IPv4 for example in this tutorial.

  It's ok to use a separated DNS name like `autoconfig.host.com` for autoconfig and autodiscover service, don't forget to setup https for it with a valid ssl cert (it's required by autodiscover).

## How autoconfig works in Thunderbird

To setup email account `user@customer.com`, Thunderbird performs the lookups below in particular order to get pre-defined server settings:

1. It checks `http://autoconfig.customer.com/mail/config-v1.1.xml?emailaddress=user@customer.com`
2. if failed, checks `http://customer.com/.well-known/autoconfig/mail/config-v1.1.xml?emailaddress=user@customer.com`

3. If failed, try to find the config of mail domain at the Mozilla ISP database (ISPDB).

   For more details about ISPDB, or you're a big ISP and want to add your domain in ISPDB, please read this tutorial.

4. Look up DNS MX record of `customer.com`. If the server specified in DNS MX record is `mx1.mail.host.com`, look up `host.com` in the ISPDB.

5. If all mechanisms failed, Thunderbird tries to guess the server address, by trying common server names like `imap.customer.com`, `smtp.customer.com`, `mail.customer.com`, etc. and, when a mail server answers, checking whether it supports SSL, STARTTLS and encrypted passwords (CRAM-MD5).

We don't control Mozilla ISPDB, and most times web site is hosted on another server, so the ideal solution is setting DNS record `autoconfig.customer.com` and pointed to your mail server. We will show you how to setup this DNS record later.

The autoconfig component configured by iRedMail Easy supports URLs:

- `https://mail.host.com/mail/config-v1.1.xml`
- `https://mail.host.com/.well-known/autoconfig/mail/config-v1.1.xml`
- `https://autoconfig.host.com/mail/config-v1.1.xml` (DNS A record of `autoconfig.host.com` must be pointed to IP of your mail server `a.b.c.d`.)
- `https://autoconfig.host.com/.well-known/autoconfig/mail/config-v1.1.xml` (DNS A record of `autoconfig.host.com` must be pointed to IP of your mail server `a.b.c.d`.)

## How auto-discover works in Microsoft Outlook

Warning

Outlook requires a valid ssl cert, a self-signed ssl cert may fail.

Without Microsoft Exchange, the order of logic that Outlook 2007 and newer releases use when trying to figure out where to get server settings is as follows:

1. HTTPS root domain query. Outlook uses the domain part of user email address to do this query, so it's `https://customer.com/autodiscover/autodiscover.xml`.
2. If above failed, try HTTPS autodiscover domain: `https://autodiscover.customer.com/autodiscover/autodiscover.xml`.
3. If above failed, try same URL but HTTP instead: `http://autodiscover.customer.com/autodiscover/autodiscover.xml`
4. If all failed, try DNS SRV record: `_autodiscover._tcp.customer.com`. If it returns a web host name and port number, for example, `mail.host.com` and port number 443, then try `https://mail.host.com:443/autodiscover/autodiscover.xml`

The ideal solution is setting DNS SRV record `_autodiscover._tcp.customer.com` and point to your server `mail.host.com`.

The autodiscover component configured by iRedMail Easy supports URLs:

- `https://mail.host.com/autodiscover/autodiscover.xml`
- `https://autodiscover.host.com/autodiscover/autodiscover.xml` (DNS A record of `autodiscover.host.com` must be pointed to IP of your mail server `a.b.c.d`.)

## Setup DNS record for autoconfig

Please create either a DNS A or CNAME record `autoconfig.customer.com` for your customer's domain name:

- For DNS A record, please point to your mail server IP address `a.b.c.d`.
- For DNS CNAME record, please point to your mail server hostname `mail.host.com`.

After created, you may need to wait for 2 or more hours until your DNS vendor flush the DNS cache. Then you can test the autoconfig with curl commands below:

    curl -k http://autoconfig.customer.com/.well-known/autoconfig/mail/config-v1.1.xml?emailaddress=user@customer.com
    curl -k http://mail.host.com/mail/config-v1.1.xml?emailaddress=user@customer.com
    curl -k http://mail.host.com/.well-known/autoconfig/mail/config-v1.1.xml?emailaddress=user@customer.com

It should print a XML format content on console.

## Setup DNS record for autodiscover

Please create a DNS SRV record for your customer's domain name `customer.com`:

- `Service`: _autodiscover
- `Protocol`: _tcp
- `Port Number`: 443
- `Host`: mail.host.com

Outlook will query DNS SRV record `_autodiscover._tcp.customer.com` first, then fetch pre-defined server settings from URL `https://mail.host.com/autodiscover/autodiscover.xml`.

After created, you may need to wait for 2 or more hours until your DNS vendor flush the DNS cache. Then try to query it with `dig` command like below:

    # dig +short -t srv _autodiscover._tcp.customer.com
    1 1 443 mail.host.com.

Create temporary text file `/tmp/outlook.xml` with content below:

    <?xml version="1.0" encoding="utf-8" ?>
    <Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/requestschema/2006">
        <Request>
            <AcceptableResponseSchema>http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a</AcceptableResponseSchema>

            <!-- EMailAddress: indicates the user's email address. OPTIONAL -->
            <EMailAddress>user@customer.com</EMailAddress>
        </Request>
    </Autodiscover>

Create temporary text file `/tmp/eas.xml` with content below:

    <?xml version="1.0" encoding="utf-8"?>
    <Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/mobilesync/requestschema/2006">
        <Request>
            <EMailAddress>user@customer.com</EMailAddress>
            <AcceptableResponseSchema>http://schemas.microsoft.com/exchange/autodiscover/mobilesync/responseschema/2006</AcceptableResponseSchema>
        </Request>
    </Autodiscover>

Now run `curl` commands to verify it:

    curl -k -X POST -d @/tmp/outlook.xml https://autodiscover.customer.com/autodiscover/autodiscover.xml
    curl -k -X POST -d @/tmp/eas.xml https://autodiscover.customer.com/autodiscover/autodiscover.xml

    curl -k -X POST -d @/tmp/outlook.xml https://mail.host.com/autodiscover/autodiscover.xml
    curl -k -X POST -d @/tmp/eas.xml https://mail.host.com/autodiscover/autodiscover.xml

It should print XML format content on console.