Exam N10-008 topic 1 question 86 discussion

When a client gets a DNS reply from a query, it will store it locally (cached) for a period of time to reduce the number of lookups on the DNS servers. In each DNS reply there is a field called TTL, or time to live. This instructs the client how long to store the replay before requesting again. This allows us to reduce the network workload and keep the DNS data fresh on the client. All devices use a cache system that stores the requests locally for a period of time and the time to live (TTL) value tells the client how long that should be.

TTL (Time to Live) should be adjusted to address the issue. The TTL determines the amount of time a record remains cached on a DNS server before it is considered expired and must be retrieved again. If the TTL is set too low, it can result in visitors being unable to access the website because they are accessing a cached, outdated version of the DNS record.

Fun fact to make this question confusing. The SOA has a serial number that sometimes needs to be manually updated so the devices that are accessing it know that they need to update their cache. So if you reduce your TTL, the cache will take less time to be updated, but updating the serial number will instantly tell the devices trying to access it that their cache data needs to be updated. Even though this may be the case, the answer is still A. TTL but hey, the more you know.

TTL determines the amount of time a record remains cached on a DNS server. The user could be trying to access the old cache data that no longer leads to the correct location.