diff --git a/Dockerfile b/Dockerfile
index ae4c04f..5f10478 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -61,7 +61,7 @@ VOLUME     [ "/var/spool/postfix", "/etc/postfix", "/etc/opendkim/keys" ]
 USER       root
 WORKDIR    /tmp
 
-HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --start-interval=2s --retries=3 CMD printf "EHLO healthcheck\nquit\n" | { while read l ; do sleep 1; echo $l; done } | nc -w 2 127.0.0.1 587 | grep -qE "^220.*ESMTP Postfix"
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --start-interval=2s --retries=3 CMD /scripts/healthcheck.sh
 
 EXPOSE     587
 CMD        [ "/bin/sh", "-c", "/scripts/run.sh" ]
diff --git a/helm/mail/values.yaml b/helm/mail/values.yaml
index 32b9ba9..82bca42 100644
--- a/helm/mail/values.yaml
+++ b/helm/mail/values.yaml
@@ -209,9 +209,7 @@ readinessProbe:
     command:
       - sh
       - -c
-      - >-
-        [ ! -f /tmp/container_is_terminating ] &&
-        printf "EHLO healthcheck\nquit\n" | { while read l ; do sleep 1; echo $l; done } | nc -w 2 127.0.0.1 587 | grep -qE "^220.*ESMTP Postfix"
+      - /scripts/healthcheck.sh
 livenessProbe:
   initialDelaySeconds: 5
   periodSeconds: 5
diff --git a/scripts/healthcheck.sh b/scripts/healthcheck.sh
new file mode 100644
index 0000000..abc95ae
--- /dev/null
+++ b/scripts/healthcheck.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+set -e
+if [ -f /tmp/container_is_terminating ]; then
+    exit 0
+fi
+
+check_postfix() {
+    printf "EHLO healthcheck\nquit\n" | \
+    { while read l ; do sleep 1; echo $l; done } | \
+    nc -w 2 127.0.0.1 587 | \
+    grep -qE "^220.*ESMTP Postfix"
+}
+
+check_dkim() {
+    if [ -f /tmp/no_open_dkim ]; then
+        return
+    fi
+    printf '\x18Clocalhost\x004\x00\x00127.0.0.1\x00' | nc -w 2 127.0.0.1 8891
+}
+
+check_postfix
+check_dkim
diff --git a/scripts/opendkim.sh b/scripts/opendkim.sh
index 1f27bfd..385b4e0 100755
--- a/scripts/opendkim.sh
+++ b/scripts/opendkim.sh
@@ -9,8 +9,10 @@ noop() {
 }
 
 if [ ! -d /etc/opendkim/keys ]; then
+    touch /tmp/no_open_dkim
     noop
 elif [ -z "$(find /etc/opendkim/keys -type f ! -name .)" ]; then
+    touch /tmp/no_open_dkim
     noop
 else
     exec /usr/sbin/opendkim -D -f -x /etc/opendkim/opendkim.conf