About DNS
What resolver does Intermapper OSX use for its DNS?
Intermapper uses two different DNS resolvers. When you add a device using the Add Device...command, Intermapper uses the system resolver, configured in the OSX Network settings panel. When you use the DNS Check feature, Intermapper does its own DNS operations, using UDP packets, to the domain name servers listed in the DNS Monitor Preferences panel. Intermapper's built-in domain name resolver assumes that the domain name is fully-qualified. The interval for verifying the domain name is determined by the TTL in each DNS response (with the minimum interval specified in the DNS Monitor preferences panel).
When you discover devices, Intermapper initially looks up the FQDN name from the IP address (address > name), it settles down to monitoring the domain name (name > address). Intermapper's built-in DNS resolver doesn't handle partially-qualified or invalid domain names; they fail to resolve.
Intermapper sometimes does not show a device DNS name...
From the Edit menu, you can select the Set Info submenu and select Set Address to change the DNS option for each affected device fromResolve name to address to Resolve address to name. With this setting, Intermapper always resolves the address to a name, and you do not see errors with names that are not fully-qualified domain names.
What is a FQDN?
FQDN is an acronym for a Fully-Qualified Domain Name. Within an organization, it is convenient to refer to a computer by the first part of its name, knowing that everyone knows that the remainder is the same as the other computers in the organization. Thus, you can speak of sneezy and dopey, knowing that they are really two computers at seven-dwarves.org.
To identify a computer uniquely, you need the FQDN, such as sneezy.seven-dwarves.org. Most user software can add a search domain to a partially-qualified domain name, adding the missing part of the FQDN. Some DNS servers require the FQDN to work properly with Intermapper. It is always best to enter the full domain name.
Even though you enter a FQDN when specifying a computer, you can use the Short, Smart Name when constructing a label for a device.
Technically, a FQDN requires a period (.) at the end. Just as the search domain is tacked onto the end of a partial domain name, most user software adds the trailing period (.).