Mail autoconfig & autodiscover

Autoconfig (Thunderbird) and Autodiscover (Outlook) are standards that let a mail client find your IMAP/SMTP settings from just your email address. No manual server/port entry.

How a client finds the settings

Thunderbird checks, in order:

1. https://autoconfig.<yourdomain>/mail/config-v1.1.xml
2. https://<yourdomain>/.well-known/autoconfig/mail/config-v1.1.xml

Outlook checks:

1. https://autodiscover.<yourdomain>/autodiscover/autodiscover.xml
2. SRV: _autodiscover._tcp.<yourdomain>

What VexaNode publishes

For domains we manage mail for, we publish:

Record	Value
A autoconfig	mail host
A autodiscover	mail host
SRV _imaps._tcp	0 1 993 mail.<domain>
SRV _submission._tcp	0 1 587 mail.<domain>
SRV _autodiscover._tcp	0 1 443 autodiscover.<domain>

Plus the XML files served over HTTPS at the two well-known paths.

Hosting your own

If you run your own mail server, host an XML file describing your servers and point autoconfig.yourdomain at it over HTTPS with a valid certificate. Example (Thunderbird config-v1.1.xml):

<clientConfig version="1.1">
  <emailProvider id="example.com">
    <domain>example.com</domain>
    <incomingServer type="imap">
      <hostname>mail.example.com</hostname>
      <port>993</port>
      <socketType>SSL</socketType>
      <authentication>password-cleartext</authentication>
      <username>%EMAILADDRESS%</username>
    </incomingServer>
    <outgoingServer type="smtp">
      <hostname>mail.example.com</hostname>
      <port>587</port>
      <socketType>STARTTLS</socketType>
      <authentication>password-cleartext</authentication>
      <username>%EMAILADDRESS%</username>
    </outgoingServer>
  </emailProvider>
</clientConfig>

INFO

The HTTPS certificate for autoconfig. and autodiscover. must be valid — clients refuse to trust self-signed certs here, which is exactly how attackers would hijack your mail settings.