diff --git a/docs/firststeps-rp.md b/docs/firststeps-rp.md
index 104aa6b34..494b67a1c 100644
--- a/docs/firststeps-rp.md
+++ b/docs/firststeps-rp.md
@@ -8,7 +8,7 @@ HTTP_PORT=8080
 HTTPS_BIND=127.0.0.1
 HTTPS_PORT=8443
 ```
-**IMPORTANT:** Do not use port 8081!
+**IMPORTANT:** Do not use port 8081, 9081 or 65580!
 
 Recreate affected containers by running `docker-compose up -d`.