diff --git a/entrypoint.sh b/entrypoint.sh
index 59d640a..9cb200e 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -55,7 +55,7 @@ fi
 opts=(
 	dc_local_interfaces "[${BIND_IP:-0.0.0.0}]:${PORT:-25} ; [${BIND_IP6:-::0}]:${PORT:-25}"
 	dc_other_hostnames "${OTHER_HOSTNAMES}"
-	dc_relay_nets "$(ip addr show dev ${NET_DEV:-eth0} | awk '$1 == "inet" { print $2 }' | xargs | sed 's/ /:/g')${RELAY_NETWORKS}"
+	dc_relay_nets "$(ip addr show dev "${NET_DEV:-eth0}" | awk '$1 == "inet" { print $2 }' | xargs | sed 's/ /:/g')${RELAY_NETWORKS}"
 )
 
 if [ "$DISABLE_IPV6" ]; then