http://blogs.technet.com/srd/archive/2008/04/09/ms08-020-how-predictable-is-the-dns-transaction-id.aspxToday we released MS08-020 to address a weakness in the Transaction ID (TXID) generation algorithm in the DNS client resolver. The TXID is a 16-bit entity that is primarily used as a synchronization mechanism between DNS servers/clients; in fact, youen-USCommunityServer 2.1 SP1 (Build: 61025.2)