Domain Matching

An alias can be:

• a short alias like app
• an FQDN (Fully Qualified Domain Name) alias like app.example.com
• a leading-label wildcard alias like *.example.com

Docker

By default, the container name is used as the short alias unless proxy.aliases is set.

General

Without match_domains

If match_domains is not set in config.yml, below will match route with short alias app:

• app.anydomain.com
• app.*.anydomain.com
• ...

Below will match route with FQDN alias app.example.com:

• app.example.com
• app.example.com.*

Below will match route with wildcard alias *.example.com:

• foo.example.com
• bar.example.com

And will not match:

• example.com
• foo.bar.example.com

Using match_domains

Use this to restrict which base domains are valid.

With match_domains in config.yml:

match_domains:
  - example.com
  - example.org

Then a short alias app can be accessed only at:

• app.example.com
• app.example.org

And a route with FQDN alias app.example.com can be accessed at:

• app.example.com

And a wildcard alias *.example.com can be accessed only at one-label subdomains such as:

• foo.example.com
• bar.example.com

but not:

• foo.bar.example.com

Priority

Host resolution order is:

1. existing exact/FQDN or short-alias domain match
2. wildcard alias fallback

This keeps normal exact-route matching fast while still allowing wildcard aliases.

Route file example

Quote wildcard aliases in YAML route files:

"*.example.com":
  host: 10.0.0.20
  port: 8080

Use case example for match_domains

Given your main domain is my.app:

• Add my.app to autocert.domains and match_domains in config.yml.

  autocert:
    domains:
      - my.app
  match_domains:
    - my.app

• Use short aliases like adguard and sonarr when you want them accessible under your main domain.

  services:
    adguard: # adguard.my.app
      ...
      labels:
        proxy.aliases: adguard
    sonarr: # sonarr.my.app
      ...
      labels:
        proxy.aliases: sonarr

• Use FQDN aliases like adguard.other.app and sonarr.other.app when you want them accessible under other domains.

  # docker compose
  services:
    adguard:
      ...
      labels:
        proxy.aliases: adguard.other.app
    sonarr:
      ...
      labels:
        proxy.aliases: sonarr.other.app
  
  # config.yml
  autocert:
    domains:
      - my.app