Enum ResolverUsage

pub enum ResolverUsage {
    Normal,
    Loopback,
    LinkLocal,
    NxDomain,
}

Name Resolution APIs and Libraries:

Are writers of name resolution APIs and libraries expected to make their software recognize these names as special and treat them differently? If so, how?

Variants

Normal

Name resolution APIs and libraries SHOULD NOT recognize these names as special and SHOULD NOT treat them differently. Name resolution APIs SHOULD send queries for these names to their configured caching DNS server(s).

Name resolution APIs and libraries SHOULD NOT recognize test names as special and SHOULD NOT treat them differently. Name resolution APIs SHOULD send queries for test names to their configured caching DNS server(s).

Name resolution APIs and libraries SHOULD NOT recognize example names as special and SHOULD NOT treat them differently. Name resolution APIs SHOULD send queries for example names to their configured caching DNS server(s).

Loopback

Name resolution APIs and libraries SHOULD recognize localhost names as special and SHOULD always return the IP loopback address for address queries and negative responses for all other query types. Name resolution APIs SHOULD NOT send queries for localhost names to their configured caching DNS server(s).

LinkLocal

Link local, generally for mDNS

Any DNS query for a name ending with “.local.” MUST be sent to the mDNS IPv4 link-local multicast address 224.0.0.251 (or its IPv6 equivalent FF02::FB). The design rationale for using a fixed multicast address instead of selecting from a range of multicast addresses using a hash function is discussed in Appendix B. Implementers MAY choose to look up such names concurrently via other mechanisms (e.g., Unicast DNS) and coalesce the results in some fashion. Implementers choosing to do this should be aware of the potential for user confusion when a given name can produce different results depending on external network conditions (such as, but not limited to, which name lookup mechanism responds faster).

NxDomain

Name resolution APIs and libraries SHOULD recognize “invalid” names as special and SHOULD always return immediate negative responses. Name resolution APIs SHOULD NOT send queries for “invalid” names to their configured caching DNS server(s).

Trait Implementations

impl Clone for ResolverUsage

fn clone(&self) -> ResolverUsage

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl PartialEq for ResolverUsage

fn eq(&self, other: &ResolverUsage) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for ResolverUsage

impl Eq for ResolverUsage

impl StructuralPartialEq for ResolverUsage