diff --git a/xCAT-server/lib/xcat/plugins/AAsn.pm b/xCAT-server/lib/xcat/plugins/AAsn.pm
index b5f82c779..c596a3176 100644
--- a/xCAT-server/lib/xcat/plugins/AAsn.pm
+++ b/xCAT-server/lib/xcat/plugins/AAsn.pm
@@ -1503,10 +1503,10 @@ sub enable_TFTPhpa
 
     if (-x "/usr/sbin/in.tftpd") {
 	system("killall in.tftpd"); #xinetd can leave behind blocking tftp servers even if it won't start new ones
-    if ($distro !~ /ubuntu.*/i){
-            system("stop tftpd-hpa");
+    if ($distro =~ /ubuntu.*/i){
+        system("stop tftpd-hpa");
     }
-        my @tftpprocs=`ps axf|grep -v grep|grep in.tftpd`;
+    my @tftpprocs=`ps axf|grep -v grep|grep in.tftpd`;
 	while (@tftpprocs) {
 		sleep 0.1;
 	}