protect against dns rebinds

config/config.yml

@@ -6,6 +6,8 @@ http:
       entryPoints:
         - https
         - http
+      middlewares:
+        - local-only
       tls:
         certResolver: hetzner
         domains:
@@ -38,3 +40,9 @@ http:
       redirectRegex:
         regex: "^http(s?)://(.+\\.)?urmel\\.duckdns\\.org(:[0-9]+)?(/.*$|$)"
         replacement: "http${1}://${2}urmel.de${3}${4}"
+    local-only:
+      ipAllowList:
+        sourceRange:
+          - "10.0.0.0/8"
+          - "172.16.0.0/12"
+          - "168.168.0.0/16"