diff --git a/lectures/Dockerfile b/lectures/Dockerfile
index 26c7e57..71e6fff 100644
--- a/lectures/Dockerfile
+++ b/lectures/Dockerfile
@@ -6,4 +6,4 @@ COPY . /lectures
 
 WORKDIR /lectures
 
-ENTRYPOINT ["/go/bin/present", "-base", "/go/pkg/mod/golang.org/x/tools@v0.6.0/cmd/present", "-http", ":3999", "-orighost", "p.go.manytask.org", "-use_playground", "-play=0"]
+ENTRYPOINT ["/go/bin/present", "-base", "/go/pkg/mod/golang.org/x/tools@v0.6.0/cmd/present", "-http", ":8080", "-orighost", "p.go.manytask.org", "-use_playground", "-play=0"]