UNIX Question and Answer – Network Services
UNIX MCQ – Multiple Choice Questions for exam, interview, and Entrance Test
1. What does SSH stand for in the context of UNIX network services?
a) Secure Shell
b) Simple Secure Host
c) Secure Socket Host
d) Shell Secure Host
Answer: a) Secure Shell
Explanation: SSH (Secure Shell) provides secure encrypted communication over a network and is commonly used for remote access to UNIX systems.
2. Which cryptographic protocol is commonly used by SSH for secure communication?
a) SSL
b) TLS
c) AES
d) SSH protocol
Answer: d) SSH protocol
Explanation: The SSH protocol uses cryptographic techniques to ensure secure communication between client and server.
3. What is the default port number for SSH?
a) 20
b) 21
c) 22
d) 23
Answer: c) 22
Explanation: Port 22 is the default port number for SSH communication.
4. Which command is used to establish an SSH connection to a remote server in UNIX?
a) ssh
b) scp
c) sftp
d) telnet
Answer: a) ssh
Explanation: The ssh command is used to establish a secure shell connection to a remote server in UNIX.
5. What is the primary purpose of the scp command in UNIX?
a) Secure file transfer
b) Remote shell access
c) File synchronization
d) Network diagnostics
Answer: a) Secure file transfer
Explanation: The scp (secure copy) command is used for secure file transfer between hosts over SSH in UNIX.
6. Which command is used to copy files from a local system to a remote system over SSH in UNIX?
a) scp
b) sftp
c) rsync
d) ftp
Answer: a) scp
Explanation: The scp command is used to securely copy files from a local system to a remote system over SSH in UNIX.
7. What is the primary purpose of the sftp command in UNIX?
a) Secure file transfer
b) Remote shell access
c) File synchronization
d) Network diagnostics
Answer: a) Secure file transfer
Explanation: The sftp command is used for secure file transfer between hosts over SSH in UNIX.
8. Which command is used to initiate a secure file transfer session in UNIX?
a) ssh
b) scp
c) sftp
d) telnet
Answer: c) sftp
Explanation: The sftp command initiates a secure file transfer session between hosts over SSH in UNIX.
9. What is the default port number for FTP?
a) 20
b) 21
c) 22
d) 23
Answer: b) 21
Explanation: Port 21 is the default port number for FTP (File Transfer Protocol) communication.
10. Which command is used to connect to an FTP server in UNIX?
a) connect
b) ftp
c) ssh
d) telnet
Answer: b) ftp
Explanation: The ftp command is used to establish an FTP connection to a remote server in UNIX.
11. What is the purpose of the passive mode in FTP?
a) Faster data transfer
b) More secure connection
c) To initiate data connections from the client to the server
d) To initiate data connections from the server to the client
Answer: d) To initiate data connections from the server to the client
Explanation: Passive mode in FTP allows the server to initiate data connections to the client, which is useful when the client is behind a firewall.
12. Which command is used to transfer files from a remote FTP server to a local system in UNIX?
a) get
b) put
c) mget
d) mput
Answer: a) get
Explanation: The get command is used to retrieve files from a remote FTP server in UNIX.
13. What is the purpose of the put command in UNIX FTP?
a) Upload files to a remote server
b) Download files from a remote server
c) Rename a file
d) Delete a file
Answer: a) Upload files to a remote server
Explanation: The put command is used to upload files from a local system to a remote FTP server in UNIX.
14. Which command is used to list files and directories on a remote FTP server in UNIX?
a) list
b) ls
c) dir
d) cd
Answer: b) ls
Explanation: The ls command is used to list files and directories on a remote FTP server in UNIX.
15. What is the purpose of the arp command in UNIX?
a) Display routing table
b) Display network interface information
c) Manipulate ARP cache
d) Configure network interfaces
Answer: c) Manipulate ARP cache
Explanation: The arp command is used to display and manipulate the Address Resolution Protocol (ARP) cache.
16. Which command is used to display information about active network connections in UNIX?
a) netstat
b) route
c) ifconfig
d) arp
Answer: a) netstat
Explanation: The netstat command displays information about active network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.
17. What is the primary purpose of the nfsd daemon in UNIX?
a) Manage NFS client connections
b) Manage NFS server connections
c) Manage NFS exports
d) Manage NFS file locking
Answer: b) Manage NFS server connections
Explanation: The nfsd daemon is responsible for managing NFS server connections in UNIX.
18. Which command is used to check the status of NFS client connections in UNIX?
a) nfsstat
b) showmount
c) rpcinfo
d) nfsinfo
Answer: c) rpcinfo
Explanation: The rpcinfo command is used to query information about RPC (Remote Procedure Call) services, including NFS client connections, in UNIX.
19. What is the purpose of the showmount command in UNIX?
a) Display mounted file systems
b) Display NFS server statistics
c) Display NFS client statistics
d) Display network interfaces
Answer: a) Display mounted file systems
Explanation: The showmount command is used to display the list of mounted file systems on an NFS server in UNIX.
20. Which command is used to configure NFS exports on a UNIX system?
a) exportfs
b) nfsconfig
c) share
d) nfssetup
Answer: a) exportfs
Explanation: The exportfs command is used to configure NFS exports, allowing directories to be shared with remote clients in UNIX.
21. What is the purpose of the nfsstat command in UNIX?
a) Display NFS server statistics
b) Display NFS client statistics
c) Display network interfaces
d) Display mounted file systems
Answer: b) Display NFS client statistics
Explanation: The nfsstat command is used to display statistics about NFS client activity in UNIX.
22. Which command is used to synchronize files and directories between local and remote systems over SSH in UNIX?
a) scp
b) sftp
c) rsync
d) ftp
Answer: c) rsync
Explanation: The rsync command is used to synchronize files and directories between local and remote systems over SSH in UNIX.
23. What is the primary advantage of using rsync over traditional file transfer methods like FTP?
a) Higher transfer speed
b) Secure encryption
c) More efficient bandwidth usage
d) Better compatibility with Windows systems
Answer: c) More efficient bandwidth usage
Explanation: Rsync optimizes bandwidth usage by transferring only the differences between files, making it more efficient compared to FTP for large data transfers in UNIX.
24. Which command is used to transfer files between UNIX systems using the SSH protocol and maintain file permissions and ownership?
a) scp
b) sftp
c) rsync
d) ftp
Answer: a) scp
Explanation: The scp (secure copy) command is used to securely transfer files between UNIX systems using the SSH protocol while preserving file permissions and ownership.
25. What is the purpose of the umount command in UNIX?
a) Mount a file system
b) Unmount a file system
c) Check file system integrity
d) Display mounted file systems
Answer: b) Unmount a file system
Explanation: The umount command is used to detach a mounted file system in UNIX.
26. What is the primary purpose of the telnet command in UNIX?
a) Secure file transfer
b) Remote shell access
c) File synchronization
d) Network diagnostics
Answer: b) Remote shell access
Explanation: The telnet command is used to establish a remote shell session on a UNIX system.
27. What is the default port number for Telnet?
a) 20
b) 21
c) 22
d) 23
Answer: d) 23
Explanation: Port 23 is the default port number for Telnet communication.
28. Which command is used to connect to a remote system using Telnet in UNIX?
a) connect
b) telnet
c) ssh
d) rlogin
Answer: b) telnet
Explanation: The telnet command is used to initiate a Telnet session to a remote system in UNIX.
29. What is the primary disadvantage of using Telnet for remote access compared to SSH?
a) Lack of encryption
b) Slower connection speed
c) Limited compatibility
d) Higher resource usage
Answer: a) Lack of encryption
Explanation: Telnet lacks encryption, making it less secure compared to SSH for remote access to UNIX systems.
30. Which command is used to terminate a Telnet session in UNIX?
a) exit
b) logout
c) quit
d) close
Answer: a) exit
Explanation: The exit command is used to terminate a Telnet session in UNIX.
31. What does SMTP stand for in the context of UNIX network services?
a) Secure Mail Transfer Protocol
b) Simple Mail Transfer Protocol
c) Secure Message Transfer Protocol
d) System Mail Transfer Protocol
Answer: b) Simple Mail Transfer Protocol
Explanation: SMTP is a protocol used for sending email messages between servers.
32. Which protocol is used for sending email messages from a UNIX system to an email server?
a) HTTP
b) FTP
c) SMTP
d) POP3
Answer: c) SMTP
Explanation: SMTP (Simple Mail Transfer Protocol) is used for sending email messages from a UNIX system to an email server.
33. What is the default port number for SMTP?
a) 20
b) 21
c) 22
d) 25
Answer: d) 25
Explanation: Port 25 is the default port number for SMTP communication.
34. Which command is used to send an email message from a UNIX system using the command line?
a) mail
b) sendmail
c) email
d) smtp
Answer: b) sendmail
Explanation: The sendmail command is used to send email messages from a UNIX system using the command line.
35. What is the purpose of the mail command in UNIX?
a) Receive email messages
b) Send email messages
c) Configure email settings
d) Delete email messages
Answer: b) Send email messages
Explanation: The mail command is used to compose and send email messages from a UNIX system.
36. Which command is used to read email messages in UNIX?
a) mail
b) readmail
c) viewmail
d) fetchmail
Answer: a) mail
Explanation: The mail command is used to read email messages in UNIX.
37. What does IMAP stand for in the context of UNIX network services?
a) Internet Mail Access Protocol
b) Internet Message Access Protocol
c) Integrated Mail Access Protocol
d) Interactive Mail Access Protocol
Answer: b) Internet Message Access Protocol
Explanation: IMAP is a protocol used for retrieving email messages from a mail server.
38. Which protocol is used for retrieving email messages from a mail server to a UNIX system?
a) POP3
b) IMAP
c) SMTP
d) HTTP
Answer: a) POP3
Explanation: POP3 (Post Office Protocol version 3) is used for retrieving email messages from a mail server to a client.
39. What is the default port number for POP3?
a) 110
b) 143
c) 25
d) 993
Answer: a) 110
Explanation: Port 110 is the default port number for POP3 communication.
40. Which command is used to retrieve email messages from a POP3 server in UNIX?
a) fetchmail
b) popmail
c) getmail
d) mailpop
Answer: a) fetchmail
Explanation: The fetchmail command is used to retrieve email messages from a POP3 server in UNIX.
41. What does DNS stand for in the context of UNIX network services?
a) Domain Name System
b) Dynamic Name System
c) Distributed Name Service
d) Digital Network Service
Answer: a) Domain Name System
Explanation: DNS is a system used to translate domain names into IP addresses.
42. Which command is used to perform DNS lookups in UNIX?
a) dns
b) nslookup
c) dig
d) host
Answer: b) nslookup
Explanation: The nslookup command is used to perform DNS lookups in UNIX.
43. What is the purpose of the dig command in UNIX?
a) Display DNS records
b) Query DNS servers
c) Configure DNS settings
d) Delete DNS records
Answer: b) Query DNS servers
Explanation: The dig command is used to query DNS servers and retrieve information about domain names and IP addresses.
44. Which protocol is commonly used for secure remote access to UNIX systems?
a) FTPS
b) Telnet
c) SSH
d) RSH
Answer: c) SSH
Explanation: SSH (Secure Shell) provides secure encrypted communication over a network and is commonly used for remote access to UNIX systems.
45. What is the primary role of the shell in UNIX?
a) Manage system resources
b) Provide graphical user interface
c) Interpret and execute user commands
d) Handle file storage and retrieval
Answer: c) Interpret and execute user commands
Explanation: The shell interprets and executes user commands in UNIX, acting as the interface between the user and the operating system.
46. What does FTPS stand for in the context of UNIX network services?
a) File Transfer Protocol Secure
b) Fast Transfer Protocol Secure
c) Flexible Transfer Protocol Secure
d) Functional Transfer Protocol Secure
Answer: a) File Transfer Protocol Secure
Explanation: FTPS is an extension of FTP that adds support for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) cryptographic protocols for secure file transfer.
47. Which command is used to initiate an FTPS session in UNIX?
a) ftps
b) ftpsecure
c) ftp
d) secureftp
Answer: a) ftps
Explanation: The ftps command is used to initiate an FTPS session, providing secure file transfer capabilities in UNIX.
48. What is the primary purpose of the lftp command in UNIX?
a) Secure file transfer
b) Remote shell access
c) File synchronization
d) Network diagnostics
Answer: a) Secure file transfer
Explanation: The lftp command is a sophisticated file transfer program that supports a variety of protocols including FTP, FTPS, HTTP, HTTPS, and more, providing secure file transfer capabilities in UNIX.
49. Which command is used to perform FTP operations in batch mode in UNIX?
a) ftpbatch
b) ftp
c) ncftp
d) curl
Answer: b) ftp
Explanation: The ftp command can be used in batch mode to perform FTP operations non-interactively in UNIX.
50. What is the primary purpose of the ncftp command in UNIX?
a) Secure file transfer
b) Remote shell access
c) File synchronization
d) Network diagnostics
Answer: a) Secure file transfer
Explanation: The ncftp command is an alternative FTP client that supports FTPS, providing secure file transfer capabilities in UNIX.
