Chapter 5 - Networking devices

Question 1

Describe the LEDs on a NIC (Network interface card)

Answer 1

Usually there is one solid link light that denotes that host NIC has established its connection with the other device on the other end of the cable connected to this NIC.

There is one flickering light that flickers when data passes through the NIC.

Question 2

What are the port numbers used by DHCP server and the DHCP client?

Answer 2

DHCP server uses port number 67

DHCP client uses port number 68

Question 3

What are the most common record types in a DNS server?

Answer 3

A record (In case of IPv4), AAA record (if IPv6 address is involved) - It is the record that converts host FQDNs to IP addresses.

CName - it is like a alias to some host. It points to the original host name or FQDN.

MX records - These are used by the email addresses. It points to the email sever that is currently accepting the emails for our domain.

Question 4

What port number is used by DNS server?

Answer 4

Port no - 53

Question 5

What port number is used by Telnet and what it is used for?

Answer 5

It uses TCP port 22 and It is a terminal emulation program. Unsecured one.

Question 6

What port number is used by FTP and what it is used for?

Answer 6

It uses TCP port no 20, 21 and with this protocol, we can browse to directory systems and files on remote system and can use for file transfers. We can’t execute files with this protocol.

Question 7

What port number is used by SFTP and what it is used for?

Answer 7

It uses TCP port no 22.
It uses SSH.

Question 8

What port number is used by TFTP and what it is used for?

Answer 8

It uses UDP 69. We can only transfer files with this protocol.

Question 9

What port number is used by SMTP and what it is used for?

Answer 9

Simple Mail Transfer Protocol - It uses TCP port 25. It is the protocol used for sending emails to the SMTP server from client.

Question 10

What port number is used by POP3 and what it is used for?

Answer 10

Post Office Protocol - It uses TCP port 110. It is one of the protocol that we can use to get the email from the email sever.
It does not provide synchronization among devices.

Question 11

What port number is used by IMAP and what it is used for?

Answer 11

Internet Message Access Protocol - It is also one of the protocol for retrieving messages from the email server. It provides

It uses port no - 143

Question 12

What port number is used by IMAP and what it is used for?

Answer 12

Internet Message Access Protocol - It is also one of the protocol for retrieving messages from the email server. It provides synchronization.

It uses TCP port 143.

Question 13

What port number is used by RDP and what it is used for?

Answer 13

Remote desktop protocol - It uses TCP port 3389.
With this protocol, we can establish GUI connection with the remote computer.
Microsoft’s RDP server is called Remote Desktop Service.
Microsoft’s RDP client is called Remote Desktop connection.

Question 14

What port number is used by Transport Layer Security / Secure Socket Layer and what it is used for?

Answer 14

This is a cryptographic protocol to sent encrypted data from one host to another over the internet.
It uses X.509 certificate and asymmetric cryptography.
It does not use a particular port number.

Question 15

What port number is used by HTTP and what it is used for?

Answer 15

Hyper Text Transfer protocol - It uses 80
And HTTPS uses TCP port 443

Question 16

What port number is used by SNMP and what it is used for?

Answer 16

Simple Network Management Protocol -
We can use this protocol to manage our network. Also this protocol can gather information from the network devices and tell us accordingly whether our network is working as expected or not.

Port no - UDP 161

Question 17

What port number is used by SSH and what it is used for?

Answer 17

Secure Shell - It uses TCP port 22.
Rest of the functions are as of Telnet.
We can execute programs with this protocol.

Question 18

What port number is used by NTP and what it is used for?

Answer 18

Network Time Protocol - It uses TCP port 123.
This protocol synchronizes time on every device on a network.

Question 19

What port number is used by LDAP and what it is used for?

Answer 19

Light Weight Directory Access protocol - It uses TCP port 389.
In an active directory environment, the directory stores every information about resources in the network, hosts, user account etc.
To get this information form the directory, we use LDAP.

Question 20

What port number is used by IGMP and what it is used for?

Answer 20

Internet Group Management Protocol - This protocol manages the IP multicast groups. Devices use this protocol to join IP multicast groups etc.
It works on the network layer and does not use any port numbers.

Question 21

What port number is used by NetBios and what it is used for?

Answer 21

Network Basic Input Output System -
It uses TCP/UDP port 137 and 138.

Question 22

What port number is used by SMB and what it is used for?

Answer 22

Server Message Block - It uses TCP 445.
This is the protocol that we use in a Windows network environment to share files, printer or other network resources.

Question 23

What is the name of the process used by DHCP?

Answer 23

DORA - Discover, Offer, Request, Acknowledgement