diff --git a/Dockerfile b/Dockerfile
index f55709b..b7cd85d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,5 +8,6 @@ RUN yarn install
 COPY . .
 RUN ls -la
 EXPOSE 80
-CMD ["PORT=80 npx y-websocket"]
+ENV PORT=80
+CMD ["npx y-websocket"]