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iRedMail Easy: Setup DNS records for autoconfig and autodiscover
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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 isa.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:
-
It checks
http://autoconfig.customer.com/mail/config-v1.1.xml?emailaddress=user@customer.com
-
if failed, checks
http://customer.com/.well-known/autoconfig/mail/config-v1.1.xml?emailaddress=user@customer.com
-
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.
-
Look up DNS MX record of
customer.com
. If the server specified in DNS MX record ismx1.mail.host.com
, look uphost.com
in the ISPDB. -
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 ofautoconfig.host.com
must be pointed to IP of your mail servera.b.c.d
.)https://autoconfig.host.com/.well-known/autoconfig/mail/config-v1.1.xml
(DNS A record ofautoconfig.host.com
must be pointed to IP of your mail servera.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:
- 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
. - If above failed, try HTTPS autodiscover domain:
https://autodiscover.customer.com/autodiscover/autodiscover.xml
. - If above failed, try same URL but HTTP instead:
http://autodiscover.customer.com/autodiscover/autodiscover.xml
- 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 tryhttps://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 ofautodiscover.host.com
must be pointed to IP of your mail servera.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
: _autodiscoverProtocol
: _tcpPort Number
: 443Host
: 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.