kumo.dns.set_mx_negative_cache_ttl(DURATION)
Since: Version 2025.03.19-1d3f1f67
The functionality described in this section requires version 2025.03.19-1d3f1f67 of KumoMTA, or a more recent version.
Set the negative cache TTL that should be used when caching an MX resolution failure.
DURATION
is either a number expressed as optionally fractional seconds,
or a human readable duration string like "5s"
to specify the units.
The default value for this is "5 minutes"
.