NETWORK SECURITY
INTRODUCTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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udp/tcp 53
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tcp 21
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udp 21
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udp/tcp 427
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Detailed explanation-1: -The answer is DNS is mostly UDP Port 53, but as time progresses, DNS will rely on TCP Port 53 more heavily.
Detailed explanation-2: -Port 53 is the well-known port number for DNS. Many years ago it was common for certain DNS implementations to send queries from source port 53. These days, it is good practice to use non-privileged source ports (i.e., 1024 or greater) and to use a different, random source port for each query.
Detailed explanation-3: -Vulnerabilities in DNS Bypass Firewall Rules (UDP 53) is a Low risk vulnerability that is one of the most frequently found on networks around the world. This issue has been around since at least 1990 but has proven either difficult to detect, difficult to resolve or prone to being overlooked entirely.