In most cases you don’t need this. Thunderbird, for example, will use a shotgun approach and may find your sever using ‘common’ server names based on your email address.

But there is an RFC and other clients may need help.


This takes advantage of the RFC with an entry for IMAP and SMTP Submission

Type Name Service Protocol TTL Priority Weight Port Target
SRV @ _imap TCP auto 10 5 143
SRV @ _submission TCP auto 10 5 465

Web Autoconfig

  • Create a DNS entry for
  • Create a vhost and web root for that with the file mail/config-v1.1.xml
  • Add the contents below to that file
<?xml version="1.0"?>
<clientConfig version="1.1">
    <emailProvider id="">
      <displayName>Example Mail</displayName>
      <incomingServer type="imap">
      <outgoingServer type="smtp">
    <clientConfigUpdate url="" />


It’s traditional to match server names to protocols and we would have used “” and “”. But using ‘mail’ is popular now and it simplifies setup at several levels.

Thunderbird will try to guess at your server names, attempting to connect to for example. But many Postfix configurations have spam prevention that interfere.


Last modified April 9, 2024: restructure (100ef14)