A network technician is troubleshooting a client workstation that cannot connect to an internal server named `appserver.corp.local`. When the technician checks the local client cache using `ipconfig /displaydns`, the following output is returned:
text Record Name . . . . . : appserver.corp.local Record Type . . . . . : 1 Time To Live . . . . : 480 Data Length . . . . . : 4 Section . . . . . . . : Answer A (Host) Record . . . : 10.0.1.50
The system administrator notes that `appserver.corp.local` was recently migrated to IP address `10.0.1.150`. Which TWO of the following solutions will address the stale resolution issue on this workstation? (Select TWO.)
- Run the `ipconfig /flushdns` command on the workstation to purge the local DNS resolver cache.Cevap
- BReconfigure outbound port rules on the workstation to block TCP port 53 traffic.
- Allow the record's Time to Live (TTL) timer to expire naturally before making subsequent connection requests.Cevap
- DChange the DNS record type on the client from an A record to a CNAME record.
Cevap
Running `ipconfig /flushdns` to immediately clear the local DNS resolver cache and allowing the Time to Live (TTL) period to expire naturally are the two valid methods to resolve the stale record issue.
When a host IP address changes on the server side, workstations that have recently resolved the old IP address store that mapping in their local DNS resolver cache until the TTL expires. Running `ipconfig /flushdns` forcibly purges the cache immediately so the next request queries the server for the new IP address (`10.0.1.150`). Alternatively, waiting for the remaining TTL timer to count down to zero will cause the client to purge the entry naturally.
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Anahtar Kavram
DNS Client Cache and TTL Management