Linux+ Linux+ Networking Services and Protocols

Question 1

Which command generates an SSH key pair on a Linux system?

Accepted Answer

ssh-keygen

Answer

ssh-copy-id

Answer

ssh-agent

Answer

ssh-keyscan

Question 2

Which file on an SSH server is the primary configuration file for the SSH daemon?

Accepted Answer

/etc/ssh/sshd_config

Answer

/etc/ssh/known_hosts

Answer

~/.ssh/authorized_keys

Answer

/etc/hosts.allow

Question 3

Which DNS record type maps a hostname to an IPv4 address?

Accepted Answer

A

Answer

AAAA

Answer

CNAME

Answer

MX

Question 4

Which command provides the most detailed DNS query output, including response time and authoritative server information?

Accepted Answer

dig

Answer

host

Answer

nslookup

Answer

whois

Question 5

What TCP port does SSH use by default?

Accepted Answer

22

Answer

21

Answer

23

Answer

443

Question 6

What is the purpose of the /etc/resolv.conf file?

Accepted Answer

Define DNS nameserver addresses and search domains

Answer

Store SSH public keys for known hosts

Answer

Map IP addresses to MAC addresses via ARP

Answer

Configure network interface speed and duplex

Question 7

Which command copies a local SSH public key to a remote server's authorized_keys file?

Accepted Answer

ssh-copy-id user@host

Answer

ssh-keygen -c

Answer

scp ~/.ssh/id_rsa.pub user@host:~/.ssh/

Answer

ssh-add ~/.ssh/id_rsa.pub