I'm reading through the following dns tutorial and it has this example in it:
domain.com. IN SOA ns1.domain.com. admin.domain.com. (
12083 ; serial number
3h ; refresh interval
30m ; retry interval
3w ; expiry period
1h ; negative TTL
)
The description for the negative TTL
value says this:
1h: This is the amount of time that the name server will cache a name error if it cannot find the requested name in this file.
What are the conditions that could trigger the server to cache a name error like this? An example would be really helpful.