Final answer:
The amount of time that old DNS data remains cached on a server is determined by the Time-to-Live (TTL) value set by the DNS server administrator.
Step-by-step explanation:
The amount of time that the old DNS data remains cached on a server is determined by a value called the Time-to-Live (TTL). The TTL is set by the administrator of the DNS server and is included in the DNS record. It specifies how long the DNS data can be cached before it should be considered expired.
When a DNS query is made to a server, the server checks its cache for the corresponding DNS record. If the record is found and its TTL has not expired, the server will use the cached information. If the TTL has expired, the server will query the authoritative DNS server for updated information.
For example, if the TTL for a DNS record is set to 1 hour, other DNS servers will cache the record for 1 hour before attempting to retrieve updated information.