diff --git a/templates/opengist/docker-compose.yml b/templates/opengist/docker-compose.yml
index d4c2fee..c4f0cc4 100644
--- a/templates/opengist/docker-compose.yml
+++ b/templates/opengist/docker-compose.yml
@@ -31,6 +31,10 @@ services:
     labels:
       - "traefik.enable=true"
       - "traefik.http.routers.opengist.rule=Host(`${SUBDOMAIN}.${DOMAIN}`)"
+      # R-753: this app reads the LEFTMOST X-Forwarded-For entry, which a stranger writes once traefik keeps the
+      # tunnel's chain — so its chain is removed here (it then reads traefik's X-Real-Ip or peer; never forgeable).
+      - "traefik.http.middlewares.opengist-xff.headers.customrequestheaders.X-Forwarded-For="
+      - "traefik.http.routers.opengist.middlewares=opengist-xff"
       - "traefik.http.routers.opengist.entrypoints=websecure"
       - "traefik.http.routers.opengist.tls=true"
       - "traefik.http.routers.opengist.tls.certresolver=letsencrypt"