3.2.5 Message Processing Events and Sequencing Rules
Except as specified in this section, the message processing and sequencing rules are unchanged from [RFC4795].
[RFC4795] section 2.1 recommends (but does not require) that the responder only send UDP responses as large as is permissible without causing fragmentation. In this profile, a responder MUST send UDP responses with size up to the maximum UDP payload that can be carried over IPv4 or IPv6. The LLMNR profile responder MAY honor the maximum acceptable UDP payload size indicated by an ENDS0 OPT record in a query. If the resource records that need to be sent in the response do not all fit in the UDP packet, then the LLMNR profile responder MUST put as many resource records as can fit in the UDP packet and send the response without setting the TC bit.
The LLMNR profile responder MUST respond to queries for resource record types of A, AAAA, PTR, and ANY. The LLMNR profile responder MAY respond to queries for other resource record types, but instead SHOULD silently discard queries for other resource record types. In response to a query with resource record type of ANY, the LLMNR profile responder MUST return any eligible A and AAAA resource records per [RFC4795] section 2.6 and MAY return other types of resource records.
[RFC4795] section 4.2 specifies that an LLMNR responder SHOULD log name conflicts detected as a result of uniqueness verification. A responder in this LLMNR profile MAY log name conflicts.