diff --git a/deploy/tunnel/Dockerfile b/deploy/tunnel/Dockerfile
index ce379c4..ae9a729 100644
--- a/deploy/tunnel/Dockerfile
+++ b/deploy/tunnel/Dockerfile
@@ -1,6 +1,6 @@
 FROM alpine:3.21
 
-RUN apk add --no-cache openssh-server
+RUN apk add --no-cache openssh-server netcat-openbsd
 
 COPY sshd_config /etc/ssh/sshd_config
 COPY entrypoint.sh /usr/local/bin/tunnel-entrypoint
@@ -9,7 +9,7 @@ RUN chmod 0755 /usr/local/bin/tunnel-entrypoint
 EXPOSE 22 22000-22099
 VOLUME ["/data"]
 
-HEALTHCHECK --interval=15s --timeout=3s --start-period=5s --retries=3 \
-  CMD ssh-keyscan -T 2 -p 22 127.0.0.1 >/dev/null 2>&1 || exit 1
+HEALTHCHECK --interval=15s --timeout=3s --start-period=10s --retries=3 \
+  CMD nc -z 127.0.0.1 22 || exit 1
 
 ENTRYPOINT ["/usr/local/bin/tunnel-entrypoint"]