DYN is a pseudo-record type for handling dynamically updated hostnames that are triggered via http or https requests (as opposed to RFC 2136-style dynamic updates).
They may not be called DYN, they may not be called anything, but rather be managed through a component of a management panel specific to dynamic updates or specific API methods.
The main motivation for doing it this way is to put some logical separation between records that can be modified remotely and other records within the zone that you may want to protect from any possible remote modification.
By doing this, if the authentication credentials on a remote dynamic device are ever compromised, it cannot be used to hijack other records within the domain.
Best practices also dictate using a separate authentication string for the device password instead of the actual password corresponding to...
