http://blogs.technet.com/janelewis/archive/2007/05/01/dns-issue-on-multi-valued-records.aspxIn a large scale environment there is a known issue which has been experienced by several customers of SRV Domain Controller records disappearing from the DNS Zone File. This is caused by the following issue; As DNS is AD Integrated, the DNS data is storeden-GBCommunityServer 2.1 SP1 (Build: 61025.2)