Which Windows command is used to clear the DNS cache?

Which Windows command is used to clear the DNS cache?

• A. ipconfig /clearcache
• B. ipconfig /flushdns
• C. netsh int ip reset
• D. ping localhost

Answer: (B)

The command used to clear the DNS cache in Windows is "ipconfig /flushdns." When this command is executed, it instructs the operating system to remove all entries from the DNS resolver cache. This is particularly useful when there have been changes in DNS settings, such as updated IP addresses for websites or when troubleshooting connectivity issues caused by stale DNS records. The DNS cache stores the results of recent Domain Name System queries, which help to speed up the process of resolving domain names to IP addresses. However, if a DNS entry is outdated or incorrect, having the ability to flush the cache ensures that the next query will retrieve fresh information from the DNS server. In contrast, other options involve different functionalities. For example, while "netsh int ip reset" resets the IP stack and may resolve network issues, it does not specifically address the DNS cache. Similarly, "ping localhost" is used to check whether the TCP/IP stack is functioning properly but does not interact with the DNS cache at all. "ipconfig /clearcache" is not a valid Windows command for managing DNS cache, which further clarifies why the correct option is essential for this task.

The command used to clear the DNS cache in Windows is "ipconfig /flushdns." When this command is executed, it instructs the operating system to remove all entries from the DNS resolver cache. This is particularly useful when there have been changes in DNS settings, such as updated IP addresses for websites or when troubleshooting connectivity issues caused by stale DNS records.

The DNS cache stores the results of recent Domain Name System queries, which help to speed up the process of resolving domain names to IP addresses. However, if a DNS entry is outdated or incorrect, having the ability to flush the cache ensures that the next query will retrieve fresh information from the DNS server.

In contrast, other options involve different functionalities. For example, while "netsh int ip reset" resets the IP stack and may resolve network issues, it does not specifically address the DNS cache. Similarly, "ping localhost" is used to check whether the TCP/IP stack is functioning properly but does not interact with the DNS cache at all. "ipconfig /clearcache" is not a valid Windows command for managing DNS cache, which further clarifies why the correct option is essential for this task.