diff --git a/Dockerfile b/Dockerfile
index 8cb5f30..aedfdab 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM thegeeklab/alpine
+FROM thegeeklab/alpine@sha256:4b2e6aaa9f0ff85655b12afd5a6aa91ff72f4d0522ba03297b1417990dd21f0c
 
 LABEL maintainer="Robert Kaussow <mail@thegeeklab.de>"
 LABEL org.opencontainers.image.authors="Robert Kaussow <mail@thegeeklab.de>"