diff --git a/chrony.conf b/chrony.conf
index 807d77c..896954d 100644
--- a/chrony.conf
+++ b/chrony.conf
@@ -6,6 +6,9 @@ server ptbtime1.ptb.de iburst nts
 minsources 2
 authselectmode require
 
+# EF
+dscp 46
+
 driftfile /var/lib/chrony/drift
 ntsdumpdir /var/lib/chrony