diff --git a/src/usr/local/www/system_routes_edit.php b/src/usr/local/www/system_routes_edit.php
index aacf260026..b8d9c3a31c 100644
--- a/src/usr/local/www/system_routes_edit.php
+++ b/src/usr/local/www/system_routes_edit.php
@@ -279,7 +279,7 @@ $section->addInput(new Form_IpAddress(
 	'network',
 	'Destination network',
 	$pconfig['network']
-))->addMask('network_subnet', $pconfig['network_subnet'])->setPattern('[.a-zA-Z0-9_]+')->setHelp('Destination network for this static route');
+))->addMask('network_subnet', $pconfig['network_subnet'])->setPattern('[.a-zA-Z0-9_:]+')->setHelp('Destination network for this static route');
 
 $allGateways = array_combine(
 	array_map(function($g){ return $g['name']; }, $a_gateways),