enhanced security through HSTS headers' middleware

.gitignore

@@ -1,2 +1,2 @@
-/.env
+/.env*
 /certs.json

docker-compose.yml

@@ -12,6 +12,7 @@ services:
       # configure Let's Encrypt automatic certificates
       - --certificatesresolvers.${TRAEFIK_CERTRESOLVER}.acme.dnschallenge=true
       - --certificatesresolvers.${TRAEFIK_CERTRESOLVER}.acme.dnschallenge.provider=${TRAEFIK_DNSPROVIDER}
+      - --certificatesresolvers.${TRAEFIK_CERTRESOLVER}.acme.dnschallenge.resolvers=${TRAEFIK_DNSRESOLVERS}
       - --certificatesresolvers.${TRAEFIK_CERTRESOLVER}.acme.email=${LETSENCRYPT_EMAIL}
       - --certificatesresolvers.${TRAEFIK_CERTRESOLVER}.acme.keytype=RSA4096
       - --certificatesresolvers.${TRAEFIK_CERTRESOLVER}.acme.storage=/certs.json
@@ -35,17 +36,21 @@ services:
     labels:
       # expose Træfik using Træfik (dashboard)
       - traefik.enable=${TRAEFIK_ENABLED}
-      # configure a global whitelist for my home
+      # configure a global whitelist for accessing the Træfik dashboard
       - traefik.http.middlewares.dashboard-whitelist.ipwhitelist.sourcerange=${TRAEFIK_DASHBOARD_WHITELIST}
-      # configure the global redirect middleware
+      # configure a global middleware for redirecting HTTP to HTTPS
       - traefik.http.middlewares.http-to-https.redirectscheme.scheme=https
       - traefik.http.middlewares.http-to-https.redirectscheme.permanent=true
+      # configure a global middleware to harden security through HSTS
+      - traefik.http.middlewares.hsts.headers.stsSeconds=${TRAEFIK_STS_SECONDS}
+      - traefik.http.middlewares.hsts.headers.stsIncludeSubdomains=${TRAEFIK_STS_SUBDOMAINS}
+      - traefik.http.middlewares.hsts.headers.stsPreload=${TRAEFIK_STS_PRELOAD}
       ### Section HTTP
       - traefik.http.routers.http-${TRAEFIK_ROUTER}.entrypoints=http
       # only some people can access the dashboard, hence protect it with it's whitelist
       - traefik.http.routers.http-${TRAEFIK_ROUTER}.middlewares=dashboard-whitelist
       # redirect Træfik dashboard to HTTPS only
-      - traefik.http.routers.http-${TRAEFIK_ROUTER}.middlewares=http-to-https
+      - traefik.http.routers.http-${TRAEFIK_ROUTER}.middlewares=http-to-https,hsts
       - traefik.http.routers.http-${TRAEFIK_ROUTER}.rule=Host(`${TRAEFIK_MATCHRULE}`)
       - traefik.http.routers.http-${TRAEFIK_ROUTER}.service=api@internal
       ### Section HTTPS

env.example

@@ -8,11 +8,17 @@ TRAEFIK_NETWORK=traefik
 TRAEFIK_MATCHRULE=traefik.mydomain.com
 TRAEFIK_ROUTER=traefik_mydomain_com
 TRAEFIK_PILOT_TOKEN=
+
+# Security
 TRAEFIK_TLSENABLED=true
+TRAEFIK_STS_SECONDS=15552000
+TRAEFIK_STS_SUBDOMAINS=true
+TRAEFIK_STS_PRELOAD=true
 
 # Certificate provider
 TRAEFIK_DNSPROVIDER=hetzner
 TRAEFIK_DNSPROVIDER_ENVFILE=./.env.dnsprovider
+TRAEFIK_DNSRESOLVERS=1.1.1.1:53,1.0.0.1:53
 LETSENCRYPT_EMAIL=admin@mydomain.com
 
 # Debugging