You are the Network Admin, and you get a compliant that some of the websites are no longer accessible. You try to ping the servers and find them to be reachable. Then you type the IP address and then you try on the browser, and find it to be accessible. But they are not accessible when you try using the URL. What may be the problem?

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A. Traffic is Blocked on UDP Port 53 DNS (Domain Name System) is responsible for resolving human-readable URLs to IP addresses and communicates primarily over UDP port 53. If UDP port 53 is blocked by a firewall or ACL, DNS queries cannot reach the resolver, so hostnames cannot be resolved even though the destination servers remain reachable by direct IP. This perfectly explains the described symptom - IP access works but URL-based access fails.

Answer

B. Traffic is Blocked on UDP Port 80 HTTP uses TCP port 80, not UDP port 80; blocking this port would prevent web page content from loading even when accessed by IP address, not just by URL.

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C. Traffic is Blocked on UDP Port 54 UDP port 54 is not assigned to any standard protocol relevant to web browsing or name resolution, so blocking it would have no effect on URL-based access.

Answer

D. Traffic is Blocked on UDP Port 80 This option is identical to option B (UDP port 80) and is incorrect for the same reason - HTTP traffic runs on TCP port 80, and its blockage would affect both IP-based and URL-based access equally.

You are the Network Admin, and you get a compliant that some of the websites are no longer accessible. You try to ping the servers and find them to be reachable. Then you type the IP address and…

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