Network

Question 1

[Network]
Where is the config file for SSH?

Answer 1

/etc/ssh/sshd_config

Question 2

[Network]
What is a wildcard certificate?

Answer 2

a type of SSL/TLS certificate (using a ‘*’) that secures a domain and all of its subdomains with a single certificate.

Question 3

[Network]
What command would you use to show listening ports?

Answer 3

$ ss -tuln
OR
$ netstat -tuln

Question 4

[Network]
TCP vs UDP

Answer 4

TCP is a 3 way handshake (ie Rsync: for task that require confirmation)
UDP is a 2 way handshake (ie netstat: quicker, & often used for streaming/gaming)

Question 5

[Network]
What command to check what ports are open?

Answer 5

$ netstat -tulnp
$ ss -tulnp

Question 6

[Network]
What port does Apache run on?
Does it use TCP or UCP?

Answer 6

8080

http= port 80 / https= port 443
typically uses TCP

Question 7

[Network]
What port does DNS run on?
Does it use TCP or UCP?

Answer 7

port 53
Both TCP & UCP
Usually UCP prioritizes speed & efficiency but TCP for large files

Question 8

[Network]
What port does NFS run on?
Does it use TCP or UCP?

Answer 8

port 2049
Both TCP & UCP

Question 9

[Network]
What port does SSH run on?
Does it use TCP or UCP?

Answer 9

port 22

Question 10

[Network]
Where is the config file for SSH?

Answer 10

/etc/ssh/sshd_config