Autodiscover / Autoconfig Checker
Check whether mail clients can auto-configure for your domain
🧭 Autodiscover / Autoconfig Checker
Enter a domain. We probe the Outlook Autodiscover path (DNS, SRV, HTTPS endpoint) and the Thunderbird Autoconfig path (/mail/config-v1.1.xml and /.well-known/mail-v1.xml) and report what each finds.
Try an example: microsoft.com · gmail.com · fastmail.com
Frequently Asked Questions
Common questions about Autodiscover and Autoconfig.
What is Autodiscover?
Autodiscover is the Microsoft protocol that lets Outlook configure itself given just an email address. The client looks up autodiscover.<domain> (CNAME or A) and the _autodiscover._tcp.<domain> SRV record, then POSTs to /autodiscover/autodiscover.xml over HTTPS to fetch mailbox settings. On Microsoft 365 the endpoint is hosted for you. You just need the CNAME.
What is Autoconfig?
Autoconfig is the Mozilla equivalent. Thunderbird and other standards-compliant clients fetch https://autoconfig.<domain>/mail/config-v1.1.xml, fall back to https://<domain>/.well-known/mail-v1.xml, then finally to Mozilla's ISPDB. The XML describes IMAP, POP, and SMTP host, port, encryption, and authentication.
Do I need both?
If your users are all on Outlook (Microsoft 365 or Exchange), Autodiscover alone is enough. If you support Thunderbird, Apple Mail, or a mixed BYOD setup, publish both. The autoconfig XML is a one-time DNS plus static-file change and it cuts a lot of support tickets.
What does "endpoint reachable" really mean?
We send a HEAD request to the Autodiscover URL. We don't POST credentials, which would mean impersonating an Outlook client. A 200, 401, 403, or 405 all confirm the host is up. What matters here is that DNS resolves and TLS terminates. Outlook handles the real XML POST with the user's password.
I'm on Microsoft 365. What should this look like?
The standard Microsoft 365 record is a CNAME from autodiscover.<domain> to autodiscover.outlook.com. If your CNAME points there and the endpoint is reachable, Outlook will configure itself. The SRV record is rarely needed for M365 tenants.