Tech QOTD – Topic: Ports (Network+)

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Answer the multiple choice question shown in the figure. (Click the figure to enlarge. Text version below.)

(see answer below and video response.)

ports-MC

You are making an outbound TCP connection from your Windows 10 system to a Windows server. Which of following ports will your computer most likely use?

A. 88
B. 389
C. 3389
D. 15074


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Answer

D. 15074

Explanation. Of the listed answers, the best one is port 15074. Remember that if you are making an outbound TCP connection to a Windows server, that it will be a dynamically assigned port, and it could be different every time. Port 15074 is just one example of what could be. It could just as well be something like port 30184, or whatever! Just as long as it isn’t a reserved, assigned port such as FTP port 21. However, the dynamic assignment is governed by the operating system and will not allow that to happen. See the video solution for more, and try a netstat -an on your system – it can be very telling!

Incorrect Answers. Port 88 is the inbound port that a Windows server would utilize if it was running Kerberos. Port 389 is the inbound port that a Windows server would utilize if it was running the Lightweight Directory Access Protocol (LDAP). And port 3389 is the inbound port that a server would use if running Remote Desktop Services (RDS).

 

Video Solution:

(Answer at 0:58)