diff --git a/docker-compose.nginx.yml b/docker-compose.nginx.yml
index a709d55..70f5d50 100644
--- a/docker-compose.nginx.yml
+++ b/docker-compose.nginx.yml
@@ -27,6 +27,9 @@ services:
     ports:
       - ${HTTPS_PORT}:443
       - ${HTTP_PORT}:80
+  mattermost:
+    ports:
+      - ${CALLS_PORT}:8443/udp
 
 # Shared volume for Let's Encrypt certificate renewal with a webroot
 volumes:
diff --git a/docker-compose.without-nginx.yml b/docker-compose.without-nginx.yml
index 6e1c174..0179358 100644
--- a/docker-compose.without-nginx.yml
+++ b/docker-compose.without-nginx.yml
@@ -4,3 +4,4 @@ services:
   mattermost:
     ports:
       - ${APP_PORT}:8065
+      - ${CALLS_PORT}:8443/udp
diff --git a/env.example b/env.example
index 43c1d86..006d683 100644
--- a/env.example
+++ b/env.example
@@ -41,9 +41,10 @@ KEY_PATH=./volumes/web/cert/key-no-password.pem
 #CERT_PATH=./certs/etc/letsencrypt/live/${DOMAIN}/fullchain.pem
 #KEY_PATH=./certs/etc/letsencrypt/live/${DOMAIN}/privkey.pem
 
-## Exposed ports to the host. Inside the container 80 and 443 will be used
+## Exposed ports to the host. Inside the container 80, 443 and 8443 will be used
 HTTPS_PORT=443
 HTTP_PORT=80
+CALLS_PORT=8443
 
 # Mattermost settings
 ## Inside the container the uid and gid is 2000. The folder owner can be set with