dns-min-ttl verifiedWritten by the Hub
Shortest TTL the engine honours
in the configuration this is a line
dns-min-ttl: Lower bound on cached lifetime: records with a shorter TTL are still kept this long, so that domains publishing very short TTLs cannot force a lookup per message.
Values
- Values
positive integer- Default
· taken from the build- applying
restart required- where it can be set
in the config file · with a startup flag · as an environment variable
In detail
Large receivers sometimes publish TTLs measured in seconds. Honouring them literally would mean resolving the same MX for every message, which is a self-inflicted denial of service on one's own resolver. The directive puts a floor under that. Empty in the stock config with a documented value of 60 seconds — so the effective floor on our nodes is a built-in nobody has stated.