diff --git a/docker-compose.yml b/docker-compose.yml
index dad815f..8e8431e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -36,7 +36,7 @@ services:
       - postgres_tmp:/var/run/postgresql
       - postgres_data:/var/lib/postgresql/data
   dns.keiu.net:
-    image: coredns/coredns:1.8.4
+    image: coredns/coredns:1.8.4@sha256:6e5a02c21641597998b4be7cb5eb1e7b02c0d8d23cce4dd09f4682d463798890
     restart: unless-stopped
     expose: ["443"]
     volumes: