Discuss Linux Foundation LFCS Exam Topic 7 Question 21

What is true regarding TCP port 23?

APort 23 is the well known port for the telnet service which is a plain text protocol that should no longer be used.

BPort 23 is the well known port for the SSH service which provides secure logins.

CPort 23 is the well known port for the rlogin service which is SSL secured by default.

DPort 23 is the well known port for the system login services which are encrypted when the user runs the starttls command in his login shell.

Suggested Answer: A

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13 comments · newest first

Kiley 1 year ago

I thought starttls was for email, not login shells?

Jaclyn 1 year ago

rlogin is also outdated, but I thought it was on a different port.

Fausto 1 year ago

Wait, isn't SSH on port 22?

Tula 1 year ago

Totally agree, telnet should be avoided these days!

Robt 1 year ago

Port 23 is definitely for telnet, not secure at all.

Wei 1 year ago

I definitely remember that telnet is plain text, so I think A is the right answer, but I’m not 100% sure.

Leah 1 year ago

I’m confused because I thought SSH was on port 22, but I can't recall what port 23 is definitively.

Alba 1 year ago

I think I saw a practice question about telnet being insecure, so I’m leaning towards option A.

Nickie 1 year ago

I remember studying that port 23 is associated with telnet, but I’m not sure if it’s still used in some cases.

Mila 1 year ago

Ah, I see now. By making the process() method abstract, we're forcing the Humanoid class to implement it, which will allow the code to print "Helping... Done".

Cristina 1 year ago

Hmm, I'm a bit unsure about this one. Should we start by raising awareness or do we need to define the behavior first? I'm not sure of the best approach.

Cory 1 year ago

I remember something about the exclusion limits based on filing status, but was it $250,000 for singles?

Carri 1 year ago

This seems like a straightforward question about project metrics. I think the answer is D - all of the above.

Linux Foundation LFCS Exam - Topic 7 Question 21 Discussion