Redirect unvalid subdomain to specific URL with Traefik

Question

I would like to redirect invalid URL to a 404 error with traefik and Docker

Example : https://sub1.domain.com is a valid doamin referenced in traefik, so nothing happen https://invalid.domain.com doesn't exist in Traefik configuration, so it will redirect to https://error.domain.com

I have searched in the official documentation and the only thing I found was about redirection , but I don't know how to use them to do my purpose.

Answer 1

You should be able to do this by specifying a redirect and a replacement. You'll also need to make sure that the Host rule matches any subdomains. Here's a config for docker-compose:

services:
  traefik:
    # ...existing config
  sub1:
    # ...existing config
  error:
    # ...existing config
    labels:
      # Match all subdomains
      - traefik.frontend.rule=HostRegexp:{subdomain:[a-z]+}.domain.com
      - traefik.frontend.redirect.regex=^https?://(.*).domain.com
      - traefik.frontend.redirect.replacement=https://error.domain.com
      # Set priority to low number so matches after other rules
      - traefik.frontend.priority=1

It's even easier if you don't mind about the domain changing but instead just want to show an error as you don't need the traefik.frontend.redirect labels