diff --git a/perl-xCAT/xCAT/ServiceNodeUtils.pm b/perl-xCAT/xCAT/ServiceNodeUtils.pm
index 049831309..3ec742830 100755
--- a/perl-xCAT/xCAT/ServiceNodeUtils.pm
+++ b/perl-xCAT/xCAT/ServiceNodeUtils.pm
@@ -185,6 +185,13 @@ sub isServiceReq
       if (!exists($servicehash->{'tftpserver'})) { 
            $servicehash->{'tftpserver'} = 1;
       }
+      # On Ubuntu management node, we disabled the isc-dhcp-server in upstart,
+      # through file /etc/init/isc-dhcp-server.override, see bug 4399
+      # however, this causes a new problem, bug 4515
+      # the fix is to start dhcp server when starting xcatd
+      if (!exists($servicehash->{'dhcpserver'}) && xCAT::Utils->osver() =~ /ubuntu.*/i) {
+          $servicehash->{'dhcpserver'} = 1;
+      }
     }
     $servicenodetab->close;
 
diff --git a/xCAT-server/lib/xcat/plugins/AAsn.pm b/xCAT-server/lib/xcat/plugins/AAsn.pm
index 953a4f658..0b4d03392 100755
--- a/xCAT-server/lib/xcat/plugins/AAsn.pm
+++ b/xCAT-server/lib/xcat/plugins/AAsn.pm
@@ -544,9 +544,13 @@ sub setup_DHCP
     if (xCAT::Utils->isMN()) { # on the MN
         #my @output = xCAT::Utils->runcmd("service dhcpd status", -1);
         #if ($::RUNCMD_RC != 0)  { # not running
-        my $retcode= xCAT::Utils->checkservicestatus("dhcpd");
+        my $dhcpservice = "dhcpd"; 
+        if (-e "/etc/init.d/isc-dhcp-server") { #Ubuntu
+            $dhcpservice = "isc-dhcp-server";
+        }
+        my $retcode= xCAT::Utils->checkservicestatus($dhcpservice);
         if($retcode!=0){
-          $rc = xCAT::Utils->startservice("dhcpd");
+          $rc = xCAT::Utils->startservice($dhcpservice);
           if ($rc != 0)
           {
             return 1;