diff --git a/iptables-helper.service b/iptables-helper.service
index 30472d2..513e5a9 100644
--- a/iptables-helper.service
+++ b/iptables-helper.service
@@ -5,9 +5,9 @@ After=network.target
 [Service]
 Environment="HOME=/root"
 WorkingDirectory=/opt/iptables-helper
-ExecStartPre=sh -c "[ -f /etc/iptables.rule ] && iptables-restore /etc/iptables.rule || exit 0;"
+ExecStartPre=/bin/bash -c "[ -f /etc/iptables.rule ] && iptables-restore /etc/iptables.rule || exit 0;"
 ExecStart=/opt/iptables-helper/iptables-helper
-ExecStartPost=sh -c "iptables-save | tee /etc/iptables.rule > /dev/null"
+ExecStartPost=/bin/bash -c "iptables-save | tee /etc/iptables.rule > /dev/null"
 Restart=on-failure
 KillMode=process
 RestartSec=5s