OS X Server Caching / DNS Question our network has 3 primary public IPs (datacenter, user set a, user set b).  I would like to set up the Caching server, and am just trying to understand the breakdown of the DNS entry.

In the data portion, the  "prs=1.2.3.4,2.3.4.5,3.4.5.6" section: What does "prs" actually equate to? Peers?  If this is going into internal DNS, wouldn't I want to use the internal IP of the cache server, as opposed to the public IPs?  

Also, does this record assist the clients/devices, or the server itself?
Reading the help pages I would assume that prs stands for public range comma-separated and prn stands for public range binary network-byte-order format.

The entry(ies) go(es) to the authoritative DNS-server which is not necessarily your (internal) DNS-server.

The purpose of the entries (of the public hosts or network ranges) in the zone file is to introduce your caching server and then redirect any of the service queries (e.g. updates) of the other hosts to your caching server.

Rough example:


Your public host             ---update request-->                            Apple Update Server
Apple Update Server      ---reverse DNS look up--->                 auth. DNS server
Auth. DNS server            ---domain name/_aaplcache._tcp---> Apple Update Server
Apple Update Server      - determines the responsible caching server
Apple Update Server      ---sends public ip of caching server---> your public host
Your public host             ---update request-->                            your caching server