Somewhat tangential... clients automatically detecting correct config settings

[Dan White]

On 06/10/18 17:00 -0600, Philip Prindeville wrote:
>Hi.
>
>I was wondering how do popular clients (like Mail.app) detect what the settings should be for an email client when you initially enter the email address.
>
>Does anyone know how it tries to detect this stuff?
>
>I’m trying to set up my email server so that users don’t need to go through the painful manual configuration.
>
>Thanks,
>
>-Philip

This is Thunderbird's approach:

/**
 * Try to guess the config, by:
 * - guessing hostnames (pop3.<domain>, pop.<domain>, imap.<domain>,
 *                       mail.<domain> etc.)
 * - probing known ports (for IMAP, POP3 etc., with SSL, STARTTLS etc.)
 * - opening a connection via the right protocol and checking the
 *   protocol-specific CAPABILITIES like that the server returns.
 *
 * Final verification is not done here, but in verifyConfig().
...

See: mailnews/base/prefs/content/accountcreation/guessConfig.js in the
source.