When signing up, use the well-known mail autoconfig to auto-discover server settings

doctorlard · June 17, 2025, 12:39am

When signing up with an email address, use the .well-known mail autoconfig URL from the email domain given, to auto-discover IMAP/SMTP settings, if it exists.

Expected behavior

Enter an email address and password. Deltachat looks up the .well-known autoconfig URL on the given email address domain, if it exists, to discover the mail server domains, ports, SSL/TLS settings, etc.

Actual behavior

The .well-known URL is currently not supported.

WofWca · June 17, 2025, 7:57am

How did you determine that it’s not used?

See the code

github.com/chatmail/core

src/configure.rs

7ec732977


      
          /// Retrieve available autoconfigurations.
          ///
          /// A. Search configurations from the domain used in the email-address
          /// B. If we have no configuration yet, search configuration in Thunderbird's central database
          async fn get_autoconfig(
              ctx: &Context,
              param: &EnteredLoginParam,
              param_domain: &str,
          ) -> Option<Vec<ServerParams>> {
              // Make sure to not encode `.` as `%2E` here.
              // Some servers like murena.io on 2024-11-01 produce incorrect autoconfig XML
              // when address is encoded.
              // E.g.
              // <https://autoconfig.murena.io/mail/config-v1.1.xml?emailaddress=foobar%40example%2Eorg>
              // produced XML file with `<username>foobar@example%2Eorg</username>`
              // resulting in failure to log in.
              let param_addr_urlencoded =
                  utf8_percent_encode(&param.addr, NON_ALPHANUMERIC_WITHOUT_DOT).to_string();
          
              if let Ok(res) = moz_autoconfigure(

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doctorlard · June 17, 2025, 11:05am

Because it works in Thunderbird, but didn’t work in the Deltachat app I installed from F-droid. I admit that I did not investigate further, but if you want, I can retry and see if I can find something in the web and mail server logs. Am I looking for a particular user agent string or similar?

WofWca · June 17, 2025, 4:29pm

Is it a public server that others can test autoconfig on?

Unfortunately I don’t know which UA Delta Chat sends.