Chapter-9 : Configuring and Securing OpenSSH Service

 

Chapter 9

Configuring and Securing OpenSSH Service 

Questions:

1. The OpenSSH Secure Shell, ssh is used to securely run a shell on a remote system

                a. True b. False 

2. Create a remote interactive shell as the current user

                a. ssh remotehost       b.  ssh root@remotehost           c.  ssh  -l   remotehost

3. Connect to a remote shell as a different user (remoteuser) on a selected host (remotehost):

                a. ssh  remotehost     

                b.  ssh  root@remotehost    

                c.  ssh  -l   remoteuse@remotehost    

                d. ssh   remoteuser@remotehost

4. Execute a single command (hostname) on a remote host (remotehost) and as a remote user (remoteuser) in a way that returns the output to the local display:

                a. ssh  remoteuser@remotehost   hostname

                b. ssh  -l   remoteuser@remotehost   hostname

                c. ssh  remoteuser@remotehost  -l   hostname

                d. ssh  remoteuser.remotehost   hostname

5. The -----  command displays a list of users currently logged into the computer.

                a. top b. ps c. w d. w –f

6. the ssh command stores the server's public key in the user's ----   file

                a. ~/.ssh/known_hosts

                b. /etc/.ssh/known_hosts

                c. /etc/ssh/sshd_config

                d. ~/.ssh/sshd_config

                e. /etc/ssh/ssh_host_key*

7. Host keys are stored in -----------  on the SSH server

                a. ~/.ssh/known_hosts

                b. /etc/.ssh/known_hosts

                c. /etc/ssh/sshd_config

                d. ~/.ssh/sshd_config

                e. /etc/ssh/ssh_host_key*

8. Users can authenticate ssh logins without a password by using ---

                a. private key authentication

                b. public key authentication

                c. manual authentication

                d. public & private  key scheme

9. ssh allows users to authenticate using a private-public key scheme.

                a. True b. False

10. Key generation is done using the --------- command

                a. ssh-keygen

                b. sshkeygen

                c. sshd-keygen

                d. ssh   -keygen    

11. After generating key pair, keys are store in 

                a. Private Key =  ~/.ssh/id_rsa.pub       ;          Public Key =   ~/.ssh/id_rsa    

                b. Private Key =  ~/.ssh/id_rsa              ;          Public Key =   ~/.ssh/id_rsa.pub       

                c. Private Key =  ~/ssh/id_rsa.pub        ;          Public Key =   ~/ssh/id_rsa       

                d. Private Key =  /etc/.ssh/id_rsa.pub   ;          Public Key =   /etc/.ssh/id_rsa       

                e. Private Key =  /etc/.ssh/id_rsa          ;          Public Key =   /etc/.ssh/id_rsa.pub      

12. During key generation, there is the option to specify a passphrase which must be provided in order to access your 

                a. private key b. public key

13. the passphrase must be entered whenever the key is used, making the authentication process no longer password-less. This can be avoided using 

                a. ssh-agent b. ssh-add c. ssh-config d. sshd-config

14. Before key-based authentication can be used, the public key needs to be copied to the destination system. This can be done with -------.

                a. sshd-copy-id

                b. ssh-copy-id

                c. ssh-copy-key

                d. sshd-copy-key

15. When the key is copied to another system using ssh - copy - id, it copies the --  file by default.

                a. ~/.ssh/id_rsa.pub

                b. ~/.ssh/id_rsa

                c. /etc/sshd/known_host

                d. /etc/.ssh/id_rsa.pub

16. To  copy the public key to the correct location on a remote system(server.abc.local)

                a. ssh-copy-id        -i     ~/.ssh/id_rsa.pub     root@serverX.abc.local

                b. ssh-copy-id     ~/.ssh/id_rsa.pub     root@serverX.abc.local

                c. ssh-copy-id        -R     ~/.ssh/id_rsa.pub     root@serverX.abc.local

17. To  copy the public key of user ‘mushfiq’ to the correct location on a remote system(server.abc.local)

                a. ssh-copy-id        -i     /home/.ssh/id_rsa.pub     root@serverX.abc.local

                b. ssh-copy-id     /home/mushfiq/.ssh/id_rsa.pub     root@serverX.abc.local

                c. ssh-copy-id        -i     /home/mushfiq/.ssh/id_rsa.pub     root@serverX.abc.local

18. The OpenSSH server has an internal configuration file setting to prohibit a system login as user root. which is commented out by default in the ----------- file:

                a. /etc/ssh/ssh_config

                b. /etc/sshd/sshd_config

                c. /etc/sshd/ssh_config

                d. /etc/ssh/sshd_config

19. the root user will be unable to log into the system using the ssh command by which edited?

                a. PermitRootLogin yes

                b. PermitRootLogin no

                c. PermitRootLogin without-password

                d. PermitRootLogin with-password

                e. PasswordAuthentication no

                f. PasswordAuthentication yes

20. To allow only key-based ssh login as root with

                a. PermitRootLogin yes

                b. PermitRootLogin no

                c. PermitRootLogin without-password

                d. PermitRootLogin with-password

                e. PasswordAuthentication no

                f. PasswordAuthentication yes

21. To protect password based authentication, 

                a. PermitRootLogin yes

                b. PermitRootLogin no

                c. PermitRootLogin without-password

                d. PermitRootLogin with-password

                e. PasswordAuthentication no

                f. PasswordAuthentication yes

22. To restart the ssh service ---

                a. systemctl  restart   ssh

                b. systemctl  restart   sshd

                c. systemctl  reload   ssh

                d. systemctl  reload   sshd

23. The port number of  ssh

                a. 21 b. 22 c. 23 d. 20