diff --git a/doskast-sshd.service b/doskast-sshd.service
index 360d663..72f1920 100644
--- a/doskast-sshd.service
+++ b/doskast-sshd.service
@@ -6,6 +6,7 @@ Wants=doskast-sshd-keygen.service
 [Service]
 ExecStart=/usr/sbin/sshd \
 	-D \
+	-4 \
 	-f /etc/doskast/doskast-sshd.conf
 ExecReload=/bin/kill -HUP $MAINPID
 KillMode=process