DNS setup for Open Directory?

Hi guys, This site is so good it should be renamed support.apple.com. ;) One topic that I can't find a guide for is how the DNS needs to be set up for OpenDirectory. I first thought it was because it didn't need any special settings (just switch it on) or that is was covered well by Apples documentation. Not so, unfortulately. I get absolutely no information from Apples documentation of OD or DNS setups that explain how the DNS needs to be set up for OpenDirectory to work. By this I primarily mean the KDC - LDAP services. My ambitions were never to manage a DNS, we have a very good ISP for that. But, according to all articles about Kerberos for OD, I need to set one up anyway to make things work. Apples docs just say that there needs to be a working DNS, not that it needs to be my Mac server. Where must the DNS be located? my xServe, local subnet, anywhere? What must be added to the DNS records? BTW, please feel free to bash on my stupidity while pointing me to the obvious article I must have missed on this subject. Since OD relies on the DNS to work there probably IS an article somewhere... right?