diff --git a/docker-compose.example.yml b/docker-compose.example.yml
index 5a1b0a4ec..c7c068f02 100644
--- a/docker-compose.example.yml
+++ b/docker-compose.example.yml
@@ -31,6 +31,7 @@ services:
       - SYS_MODULE
     ports:
       - 51820:51820/udp
+      - 21820:21820/udp
       - 443:443 # Port for traefik because of the network_mode
       - 80:80 # Port for traefik because of the network_mode
 
diff --git a/install/config/docker-compose.yml b/install/config/docker-compose.yml
index 35319dd0e..4ce31e41f 100644
--- a/install/config/docker-compose.yml
+++ b/install/config/docker-compose.yml
@@ -31,6 +31,7 @@ services:
       - SYS_MODULE
     ports:
       - 51820:51820/udp
+      - 21820:21820/udp
       - 443:443 # Port for traefik because of the network_mode
       - 80:80 # Port for traefik because of the network_mode
 {{end}}