Enum MxResolveFailure 

pub enum MxResolveFailure {
    NxDomain,
    Indeterminate,
    NeverQueried,
    PolicyRejected,
}

How resolving a domain’s MX failed, classified by what the DNS exchange established. A caller that needs to act on a specific case (such as NXDOMAIN) can match on this after recovering the MxResolveError with downcast_ref, rather than matching on the message text.

Variants

NxDomain

Authoritative negative response: the resolver reported that the name does not exist (NXDOMAIN). A resolver can return NXDOMAIN spuriously, while its own upstream is still propagating a new registration, and will stop doing so once that passes. A caller should re-check after a bounded negative-cache lifetime rather than treat this as final.

Indeterminate

Indeterminate negative response: a query was issued but did not produce an authoritative answer – a timeout after the query was sent, a SERVFAIL or other failure RCODE, or a resolver I/O error. The true state of the name is unknown and a later query may resolve it.

NeverQueried

No query was ever issued: the timeout elapsed while waiting for an MX concurrency permit. Indicates local concurrency pressure, nothing about the destination.

PolicyRejected

The MX set resolved, but the domain’s MTA-STS enforce policy permits none of its own MX hosts. Mail to the domain cannot be delivered until its operator corrects the policy.

Trait Implementations

impl Clone for MxResolveFailure

fn clone(&self) -> MxResolveFailure

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MxResolveFailure

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for MxResolveFailure

fn eq(&self, other: &MxResolveFailure) -> 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 MxResolveFailure

impl Eq for MxResolveFailure

impl StructuralPartialEq for MxResolveFailure