bugfix:

- skip overwrite mac in full mac-table for unknown ip record

scripts/fetch_new_arp.pl

@@ -172,6 +172,7 @@ my @auth_full_list=get_records_sql($dbh,$auth_sql);
 foreach my $auth (@auth_full_list) {
     next if (!$auth);
     my $auth_mac=mac_simplify($auth->{mac});
+    next if (exists $auth_table{full_table}{$auth_mac});
     $auth_table{full_table}{$auth_mac}=$auth->{id};
     }