COMPTIA Security+ Tutorial: Module 01,Part 08 – TCP/IP Protocol

TCP-IP Protocol

To communicate well with the internet we need a set of language which can be called as the Transmission Communication Protocol. It can likewise be utilized as an communication protocol as a part of Extranet or Intranet. In your immediate correspondence or access to the web, a duplicate of the TCP/IP program is sent to your PC. The convention is utilized for transmitting bundles over the web.

TCP/IP is a two layered program. Out of these two the higher layer is dependable to deal with the amassing of messages or documents into littler parcels. These bundles are transmitted over the web and got by the TCP Layer where the first message will be reassembled. The second layer or the lower layers investigate the address part of the bundle with the goal that it gets to the correct goal.

TCP/IP is based on the Client/server model. In this a computer (client) is engaged to place requests to provide services such as (sending web pages) by another computer network.



Few properties of the TCP/IP protocol make it a protocol of choice. It is called as the Connection Oriented Protocol meaning that it establishes a logical connection and does proper sequencing of packets to be sent from one session to another.

This is important to keep a track on what packets will be sent and what needs to be re-sent.

Sliding Window

The Sliding Window allows TCP to check for the messages that have been sent if they have been received. If not received, the messages will be resent so TCP will not go past one sliding window until the message has been acknowledged as received.

The TCP protocol is a reliable protocol as it guarantees delivery sequencing, is connection oriented, and is preferred as the protocol of choice for delivery across the internet. The IP refers to the logical addressing, i.e. the packets traveling over the internet should be known for their source of origin and their destination.

Internet Protocol Version 4

There are two types of protocols one is Internet Protocol Version 4 and Internet Protocol Version 6. Under the IPv 4, it is a 32 bit address which has 4 octets and each octet is 8 bits long. IPv4 is used to identify the devices on a network through an addressing system. This Internet Protocol is designed for use in the interconnected systems of packet-switched computer communication networks.

It is generally used to interface the gadgets to the web. Considering the development of the web, it is expected that the Ipv4 locations will, in the end run out in light of the fact that each gadget including the PC, cell phones, and amusement consoles will require a deliver to associate with the web.

Dynamic Host Configuration Protocol

In order to make the automatic addressing effective we have the DHCP. We can get this installed on our servers through the server manager. After which,we can get authentication for our servers on the network.

Here we should understand the DHCP scope. A DHCP scope is a range of available IP addresses from which the system will lease out the possible IP addresses. The keyword is leased, so addresses are leased out.The administrators will configure the lease period that is most commonly 8 days. Another aspect of DHCP scope is to have a reservation.

The purpose of the reservation is to isolate some particular IP addresses. We have some network devices like printers, for which we would never want the IP address to change. The IP addresses that are kept in reserve can be used for the purpose.

Internet Protocol Version 6

Another Internet Protocol to provide the new addresses to connect to the internet.

It is a 128- bit address that is expressed in hexa-decimals which imply that we will see numbers and alphabets for IPv6. IPv6 is designed to allow the internet to grow steadily, both in the terms of the number of hosts connected and the total amount of data traffic transmitted. IPv6 is an enhanced version with the inclusion of the following technologies like:

  • No More NAT (Network Address Translation)
  • No more address collisions
  • Better routing
  • Simple header format
  • Efficient Routing
  • Auto-Configuration
  • Built- in authentication and privacy support
  • Flexible Options and extensions
  • Easier administration and no need of DHCP

We will now talk about the Common Protocols , what their functions are and what the port assignments are.

If we have ‘S’ at the beginning of the name, it means that its has come from the port SSH, and if we have “S” at the end of the name, means that it has come from the port SSL, where S stands for Secure.


Secured Shell

We need a, secure shell SSH, to give security to the information that will pass through the internet. The communication packets are shielded before they transmit over the internet. Its port number is 22.  It provides a secure channel for transmission, over the unsecured network in the Client-Server architecture.

It supports password-based authentication that is encrypted by automatically generated keys.

Secured Socket Layer

On the other hand, SSL is Secured Socket Layer which provides end to end security for data transmission. It is the technology that establishes the encrypted link between the client and the server. SSL maintains the highest security standards,enabling the important information like card numbers, social security numbers and others to transmit securely.

SSL secure millions of users that are involved in transmitting the data during online transactions. It will give end-to-end security.

File Transfer Protocol

It is a standard file transfer protocol and the users may authenticate themselves with the clear text sign in the protocol. For secure transmission the FTP is secured with SSL/TLS (FTPS) or SSH File Transfer Protocol (SFTP), but the technology is different in the two.

Hyper Text Transfer Protocol

It is the protocol that defines how messages are formatted and transmitted. This protocol defines what actions Web servers and browsers should take in response to various commands.

It is the protocol used by the World Wide Web. Often called as the stateless protocol as each command is executed independently without the knowledge of the command that came first. It has port number 443

Remote Desktop Protocol (RDP)

It is a propriety protocol for Microsoft. It provides users with a graphical interface to provide other computer connect over the internet. It has a port number 3389.


It has a port number 23. It does connection across the network with the  remote computers.

Simple Network Management Protocol (SNMP)

We need a protocol that can be used to collect information from, configuring network devices such as servers, printers, hubs, switches, and routers on an Internet Protocol network. With SNMP we can monitor the performance of the devices that are connected.

The port numbers are 160,161,162.

Simple Mail Transfer Protocol (SMTP)

The port number is 25 and it allows the emails to move from one server to another server.

Domain Name Service (DNS)

The port number is 53 and it allows the name resolution across the internet. The DNS maintains the table of the browsers. If you look for an information, the browser will not know where to go. It is the DNS which will take you to the web page.

Post office Protocol (POP)

This is a protocol with which we retrieve emails from the remote servers, but we do not send emails through this. These emails will be available even when we are not connected. We currently use the POP 3 versions.

The port number of POP is 110.

Internet Message Access Protocol (IMAP)

The IMAP supports the multiple logins and the port number for IMAP is 143. It allows the end users to connect simultaneously with the email server with the different devices.

This protocol stores the email messages on the mail server. The end users are allowed to view and manipulate the messages as though they were stored locally on the user’s device itself.

Internet Control Message Protocol (ICMP)

ICMP is an error reporting protocol network device that would generate error messages to the source IP address when network problems hinder the delivery of the IP packets.

It is not a transport protocol, while ICMP is not used regularly in end-user applications. The ICMP is used by routers or other intermediary devices that would communicate immediately about the error information.

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