diff -Naurp webmin-1.260.orig/virtual-server/virtual-server-lib.pl webmin-1.260/virtual-server/virtual-server-lib.pl
--- webmin-1.260.orig/virtual-server/virtual-server-lib.pl	2005-12-18 14:42:40.000000000 -0800
+++ webmin-1.260/virtual-server/virtual-server-lib.pl	2006-03-18 02:15:48.000000000 -0800
@@ -2080,7 +2080,12 @@ if (!$config{'iface_manual'}) {
 		$vmax = $b->{'virtual'}
 			if ($b->{'name'} eq $iface->{'name'} &&
 			    $b->{'virtual'} > $vmax);
+
+		if($b->{'address'} eq $_[0]->{'ip'}) {
+			print "IP address is already active.<p>\n";
+			return;
 		}
+	}
 	local $virt = { 'address' => $_[0]->{'ip'},
 			'netmask' => $net::virtual_netmask || $iface->{'netmask'},
 			'broadcast' =>