diff --git a/etc/inc/interfaces.inc b/etc/inc/interfaces.inc
index aa6bad2e1..4046d240e 100644
--- a/etc/inc/interfaces.inc
+++ b/etc/inc/interfaces.inc
@@ -2166,12 +2166,12 @@ function interface_ipalias_configure(&$vip) {
 		$af = 'inet6';
 	$iface = $vip['interface'];
 	$vipadd = '';
-	if (stripos($vip['interface'], '_vip')) {
+	if (strpos($vip['interface'], '_vip')) {
 		$carpvip = get_configured_carp_interface_list($vip['interface'], $af, 'vip');
 		$iface = $carpvip['interface'];
 		$vipadd = "vhid {$carpvip['vhid']}";
 	}
-	$if = get_real_interface($vip['interface']);
+	$if = get_real_interface($iface);
 	mwexec("/sbin/ifconfig " . escapeshellarg($if) ." {$af} ". escapeshellarg($vip['subnet']) ."/" . escapeshellarg($vip['subnet_bits']) . " alias {$vipadd}");
 	unset($iface, $af, $if, $carpvip, $vipadd);
 }