Traefik serves default certificate when using wildcard domain

Traefik Traefik v2
3

Usually every sub-domain needs a DNS entry to resolve to an IP. You created those?

Yes, I have a wildcard certificate for those.

Actually, looking at the docs, I can't see how to set the LE cert as the default one for all unknown subdomains:

  stores:
    default:
      defaultGeneratedCert:
        resolver: lets_encrypt_resolver
        domain:
          main: mydomain.com
          sans:
            - *.mydomain.com

The example only shows concrete domains specified in the sans field...

--

What do I need to do, so that I when I visit unknownsubdomain.mydomain.com, it does not show a https warning and instead redirects to mydomain.com, or anywhere else?

-- Edit: Solution is:

  • Wildcard cert
  • Redirect all http to https (I already had this)
  • Low priority route that forwards everything to another domain via middleware

Here's the redirect router:

    redirectUnknownSubdomain:
      rule: PathPrefix(`/`)
      priority: 1
      entryPoints:
        - https
      middlewares:
        - redirectUnknownSubdomain
      service: redirectUnknownSubdomain
      tls:
        certResolver: lets_encrypt_resolver
        domains:
          - main: {{env "DOMAIN"}}
          - sans: '*.{{env "DOMAIN"}}'

and the redirect service:

    redirectUnknownSubdomain:
      loadBalancer:
        servers:
          - url: https://www.google.com