Specifications

34 Appendix C
In the DNS service record lookup, an administrator can configure the DNS server to
provide server and port number for a service that will be referred to as _WCM._tcp.
Multiple configuration repository server/port values can be provided. The WCM agent will
access them in order, according to the weight and priority associated with each entry.
Since the DNS server may not supply a protocol string associated with each server/port
entry, the WCM agent will determine the protocol based on the port specified (for example,
if port 80 is specified, the WCM agent will determine the protocol being used is HTTP). If
the DNS service record lookup for _WCM._tcp fails, the WCM agent will attempt
_WCM._tcp plus a domain name, and then attempt _WCM._tcp plus each sub-domain
name upon further failures. For example, if the domain name is x.y.z, the WCM agent will
issue a DNS service location lookup using the following names (in the order shown) until
the DNS server returns a valid answer:
_ WCM._tcp.x.y.z
_ WCM._tcp.y.z
_ WCM._tcp.z
If the WCM agent is unable to obtain a valid answer to DNS service record lookup
requests, it will then attempt a DNS hostname lookup. An administrator can configure the
DNS server to provide the server IP for a host name (for example, WCM). If the DNS
server does not supply a protocol string or a port number, the retrieval module will first use
HTTPS on port 443. If this fails, the WCM agent will then use HTTP on port 80. If the
lookup for host name WCM in the client’s domain fails, the WCM agent will then attempt
WCM for each sub-domain name. For example, if the domain name is x.y.z, the WCM
agent will issue a DNS host name lookup using the following names (in the order shown)
until the DNS server returns a valid answer:
WCM.x.y.z
WCM.y.z
WCM.z