diff --git a/config/cfgroot/network-functions.pl b/config/cfgroot/network-functions.pl
index 070e14d0f..7cd56f799 100644
--- a/config/cfgroot/network-functions.pl
+++ b/config/cfgroot/network-functions.pl
@@ -139,7 +139,7 @@ sub network2bin($) {
 	my $netmask_bin = &ip2bin($netmask);
 
 	if (!defined $address_bin || !defined $netmask_bin) {
-		return undef;
+		return ();
 	}
 
 	my $network_start = $address_bin & $netmask_bin;