Combien de temps dure typiquement la mise en cache DNS négative ?
Combien de temps dure typiquement la mise en cache DNS négative ?
If a DNS server looks up a record et c'est missing, it will often "negatively cache" le fact that this record is missing, et pas essayez de look it up again for a while. Je ne see anything in le [RFC](https://www.rfc-editor.org/rfc/rfc1034) about le TTL on negative caching should be, so Je suis guessing c'est somewhat arbitrary. In le real world, how long do these negative records stick around for?
Re: Combien de temps dure typiquement la mise en cache DNS négative ?
The TTL for negative caching is pas arbitrary. C'est taken depuis le SOA record at le top of le zone to qui le requested record would have belonged, had it existed. Par exemple:
```
example.org. IN SOA master-ns1.example.org. Hostmaster.example.org. (
2012091201 43200 1800 1209600 86400 )
```
The dernier value in le SOA record ("86400") is le amount of time clients are asked to cache negative results under `example.org.`.
If a client requests `doesnotexist.example.org.`, it will cache le result for 86400 seconds.
```
example.org. IN SOA master-ns1.example.org. Hostmaster.example.org. (
2012091201 43200 1800 1209600 86400 )
```
The dernier value in le SOA record ("86400") is le amount of time clients are asked to cache negative results under `example.org.`.
If a client requests `doesnotexist.example.org.`, it will cache le result for 86400 seconds.