HTTP and HTTPS

HTTP:

HTTP is associate degree client-server protocol that enables clients to request web content from network servers. it's associate degree application level protocol widely used on the net. shoppers area unit sometimes net browsers. once a user desires to access an online page, a browser sends associate degree communications protocol Request message to the network server. The server responds with the requested web content. net servers sometimes use protocol port eighty.

Clients and net servers use request-response methodology to speak with one another, with shoppers causing the communications protocol Requests and servers responding with the communications protocol Responses. clients sometimes send their requests victimization GET or POST ways, maybe GET /homepage.html. net servers respond with a standing message (200 if the request was successful) and send the requested resource.

HTTPS:

Hypertext Transfer Protocol Secure could be a secure version of the protocol. This protocol permits secure communication between a shopper (e.g. internet browser) and a server (e.g. internet server) by victimization encoding. HTTPS uses SSL (Secure Socets Layer) protocol and for encoding and TCP port 443 for communication.

HTTPS is usually accustomed produce a secure channel over some insecure network, e.g. Internet. By default, most traffic on the web is unencrypted and prone to sniffing attacks. HTTPS encrypts sensitive data, that makes an association secure.

HTTPS is typically not used on the complete web site as a result of encoding slows down the location. Instead, it's used solely to safeguard sensitive data like usernames and passwords.

HTTPS URLs begin with protocols rather than HTTP. In web someone, you'll straightaway acknowledge that an internet website is victimization HTTPS as a result of a lock seems to the proper of the address bar.

SNMP (Simple Network Management Protocol) details

Simple Network Management Protocol (SNMP) is AN application layer protocol that's used for network device management. This protocol will collects and manipulate valuable network data from switches, routers, servers, printers, and alternative network-attached devices.

An SNMP-managed network consists of 2 components:
 

1.     Network management station (NMS) – the software system that runs on the executive pc. This software system gathers SNMP information by requiring the devices on the network to disclose sure data. Devices may inform the NMS regarding issues they're experiencing by causation AN SNMP 

2.    Agent – the software system that runs on managed devices and reports data via SNMP to the NMS.

How SNMP works?

The router R1 is organized to send SNMP traps to the NMS Station. If a retardant happens, the router can send AN SNMP lure to Host A. to Illustrate, if there's a port security violation on R1, the router can send the SNMP lure, notifying that there has been a possible security breach on the network.

NOTE – SNMP agents use a UDP port 161, whereas the manager uses a UDP port 162. this SNMP version is SNMPv3. The previous versions, SNMPv1 and SNMPv2 ar thought-about obsolete and will not be used.

What is FTP & TFTP ?

FTP (File Transfer Protocol)

FTP may be a network protocol wont to transfer files from one pc to a different over a transmission control protocol network. Like Telnet, it uses a client-network arhitecture, which implies that a user has got to have associate degree FTP shopper put in to access associate degree FTP server running on the remote machine. when establishing associate degree FTP association, the user will transfer or transfer files to and from the FTP server.

FTP uses 2 TCP ports: port twenty for causation knowledge and port twenty one for causation control commands.

FTP will use authentication, however like Telnet, all knowledge is shipped in clear text, as well as usernames and passwords.

TFTP (Trivial File Protocol)

TFTP may be a network protocol wont to transfer files between remote machines. it's an easy version of FTP, lacking a number of the additional advanced options FTP offers, however requiring less resources than FTP.

Because of it’s simplicity TFTP are often used solely to send and receive files. It uses UDP port sixty nine for communication.

Because of it’s disadvantages TFTP isn't wide used these days, however it’s wont to save associate degreed restore a router configuration or to backup an IOS image.

TFTP doesn’t support user authentication and sends all knowledge in clear text.

Telnet and SSH

What is telnet?

Telnet could be a network protocol that enables a user to communicate with a distant device. it's a virtual terminal protocol used principally by network administrators to remotely access and manage devices. an administrator will access the device by “telnetting” to the IP address or hostname of a distant device.

To use telnet, you want to have a code (Telnet client) put in. On a distant device, a Telnet server should be installed and running. Telnet uses TCP port twenty-three.

One of the main disadvantages of this protocol is that all data i.e usernames and passwords, is sent in clear text and that could be a potential security risk. This is often the most reason why Telnet isn't used nowadays and is being replaced by a far secure protocol known as SSH.

The word “telnet” can even confer with the software that implements the telnet protocol.
On Windows, you'll be able to begin a Telnet session by writing the telnet IP_ADDRESS or HOSTNAME command:

telnte-ccna-tutorials

What is SSH?

The SSH protocol (also referred to as Secure Shell) is a technique for secure remote login from one pc to a different. It provides many different choices for robust authentication, and it protects the communications security and integrity with robust cryptography.

SSH-CCNA-TUTORIALS

What is DHCP? How it works?

What is DHCP?

Dynamic Host Configuration Protocol (DHCP) is a protocol. It helps a server machine to automatically assign an IP address to a Device from a defined range of numbers configured for a given network.

Usually when we connect wifi network to our mobile/laptop then wifi router connect it and provide an IP Address automatically. Do you think which protocol is used for this? In this case basically, DHCP protocol is used. (Some Exceptional case wifi router also use static IP Address also).
 

How DHCP Work?

Here is how the DHCP process works when you go online:

1)    Your go on your computer to connect to the Internet.

2)    The network requests an IP address (this is actually referred to as a DHCP discover message).

3)    On behalf of your computer's request, the DHCP server allocates (leases) to your computer an IP address. This is referred to as the DHCP offer message.

4)    Your computer (if you're the DHCP client) takes the first IP address offer that comes along. Then it responds with a DHCP request message who verifies the IP address that's been offered and obtained.

5)    DHCP then updates the appropriate network servers with the IP address and other configuration information for your computer.

6)    Your computer (or whatever network device you're using) accepts the IP address for the lease term.

What is ARP(Address Resolution Protocol)?

What is ARP(Address Resolution Protocol)?

 

Address Resolution Protocol (ARP) is a low-level network protocol for translating network layer addresses into link layer addresses.

ARP lies between layers 2 and 3 of the OSI model, although ARP was not included in the OSI framework and allows computers to introduce each other across a network prior to communication.

Because protocols are basic network communication units, address resolution is dependent on protocols such as ARP, which is the only reliable method of handling required tasks.

ARP-CCNA-TUTORIALS

UDP

UDP

One of the important protocols in the TCP/IP site is User Datagram Protocol (UDP). UDP is basically a scaled-down version of TCP. Just like TCP, this protocol provides delivery of data between applications running on hosts on a TCP/IP network, unlike TCP, it does not sequence the data and does not care about the order in which the segments arrive at the destination. Because of this it is considered to be an unreliable protocol. UDP is also considered to be a connection-less protocol, since no virtual circuit is established between two endpoints before the data transfer takes place.

UDP application

Here are few applications where UDP is used to transmit data:

Domain Name Services

Simple Network Management Protocol

Trivial File Transfer Protocol

Routing Information Protocol

Kerberos

TCP/IP suite of protocols

TCP/IP suite of protocols

The TCP/IP suite is the set of protocols used on a computer networks today. It provides end-to-end connectivity by specifying how data should be packed, addressed, transmitted, routed and received on a TCP/IP network. This functionality is organized into four abstraction layers and each protocol in the suite resides in a particular layer.

The TCP/IP suite is named after its most important protocols, the Transmission Control Protocol (TCP) and the Internet Protocol (IP). Some of the protocols included in the TCP/IP suite are:

1.            ARP (Address Resolution Protocol) – used to convert an IP address to a MAC address.

2.            IP (Internet Protocol) – used to deliver packets from the source host to the destination host based on the IP addresses.

3.           ICMP (Internet Control Message Protocol) – used to detects and reports network error conditions. Used in ping.

4.            TCP (Transmission Control Protocol) – a connection-oriented protocol that enables reliable data transfer between two computers.

5.            UDP (User Datagram Protocol) – a connection less protocol for data transfer. Since a session is not created before the data transfer, there is no guarantee of data delivery.

6.            FTP (File Transfer Protocol) – used for file transfers from one host to another.

7.            Telnet (Telecommunications Network) – used to connect and issue commands on a remote computer.

8.            DNS (Domain Name System) – used for host names to the IP address resolutions.

What is TCP?

What is TCP?

One of the main protocols in the TCP/IP suite is Transmission Control Protocol (TCP). TCP provides reliable and ordered delivery of data between applications running on hosts on a TCP/IP network. Because of its reliable nature, TCP is used by applications that require high reliability, such as FTP, SSH, SMTP, HTTP, etc.

TCP is connection-oriented, which means that, before data is sent, a connection between two hosts must be established. The process used to establish a TCP connection is known as the three-way handshake. After the connection has been established, the data transfer phase begins. After the data is transmitted, the connection is terminated. One of the main protocols in the TCP/IP suite is Transmission Control Protocol (TCP).

One other notable characteristic of TCP is its reliable delivery. TCP uses sequence numbers to identify the order of the bytes sent from each computer so that the data can be reconstructed in order. If any data is lost during the transmission, the sender can retransmit the data.

Types of IP addresses

Types of IP addresses

What is IP Address?

The IP address is a familiar for most computer users. An IP address is the unique numerical address of a device in a computer network that uses Internet Protocol for communication.

An IP address consists of four numbers and each can contain one to three digits. These numbers are separated with a single dot (.). These four numbers can range from 0 to 255 each.

Types of IP addresses

The IP addresses can be classified into two Types. They are listed below.

1) Static IP addresses

2) Dynamic IP addresses

Static IP Addresses

As the name indicates, the static IP addresses usually never change but they may be changed as a result of network administration. They serve as a permanent Internet address and provide a simple and reliable way for the communication. From the static IP address of a system, we can get many details such as the continent, country, region and city in which a computer is located, The Internet Service Provider (ISP) that serves that particular computer and non-technical information such as precise latitude and longitude of the country,  and the locale of the computer. It is the easiest system to find your IP address by http://whatismyip.org/.

Dynamic IP Addresses

Dynamic IP address are the second category. These are temporary IP addresses. These IP addresses are assigned to a computer when they get connected to the Internet each time. They are actually borrowed from a pool of IP addresses, shared over various computers. Since limited number of static IP addresses are available, ISPs usually reserve the portion of their assigned addresses for sharing among their subscribers in this way.

Static IP addresses are considered as less secure than dynamic IP addresses because they are easier to track.

There are only two version of IP address. These are IP Version 4 and IP Version 6

How many types of network?

How many types of network?

 
There are mainly three types of network. 

1.    LAN = Local Area Network.

2.    MAN = Metropolitan Area Network.

3.    WAN = Wide Area Network.

LAN: This is one of the original categories of network, and one of the simplest.  LAN networks connect computers together over relatively small distances, such as within a single building or within a small group of buildings.

MAN: This is a network which is larger than a LAN but smaller than a WAN, and incorporates elements of both. It typically spans a town or city and is owned by a single person or company, such as a local council or a large company.

WAN: This is another of the original categories of network, and slightly more complex in nature. WAN networks connect computers together over large physical distances, remotely connecting them over one huge network and allowing them to communicate even when far apart.

Types of Ethernet Cabling

Types of Ethernet Cabling

 
There are three cable types of Cable commonly used for Ethernet cabling:

1.    Coaxial.
2.    Twisted pair.
3.    Fiber-optic cabling.

Now a days the twisted pair cabling is the most popular type of cabling, but the fiber-optic cabling usage is increasing, especially in high performance networks. Coaxial cabling is generally used for cable Internet access. Btu for remote connectivity people's are now use Fiber-optic cable.

Simplex, Half Duplex and Full Duplex

Communication channels

 In Telecommunication and Computer Networking there are three types of communication channels. These are:

1.    Simplex: A simplex communication channel only sends information in one direction.

2.    Half Duplex: In  half duplex mode, data can be transmitted in both directions on a signal carrier except not at the same time.

3.    Full Duplex: A full duplex communication channel is able to transmit data in both directions on a signal carrier at the same time.

These communication channels provide a way to express information.

IEEE Ethernet Standards

Ethernet defined a number of IEEE (Institute of Electrical and Electronics Engineers) 802.3 standards. These standards define the physical and data-link layer specifications for Ethernet. Some most important 802.3 standards are:

10Base-T (IEEE 802.3) – 10 Mbps with category 3 unshielded twisted pair (UTP) wiring, up to 100 meters long.

100Base-TX (IEEE 802.3u) – Known as Fast Ethernet, uses category 5, 5E, or 6 UTP wiring, up to 100 meters long.
 
100Base-FX (IEEE 802.3u) – Version of Fast Ethernet that uses multi-mode optical fiber. Up to 412 meters long.
 
1000Base-CX (IEEE 802.3z) – Uses copper twisted-pair cabling. Up to 25 meters long.
 
1000Base-T (IEEE 802.3ab) – Gigabit Ethernet that uses Category 5 UTP wiring. Up to 100 meters long.
 
1000Base-SX (IEEE 802.3z) – 1 Gigabit Ethernet running over multimode fiber-optic cable.
 
1000Base-LX (IEEE 802.3z) – 1 Gigabit Ethernet running over single-mode fiber.
 
10GBase-T (802.3.an) – 10 Gbps connections over category 5e, 6, and 7 UTP cables.

MAC and IP Address

What is MAC Address?

MAC- Media Access Control (MAC) address is a 48-bit address which is used for communication between two hosts in an Ethernet environment. It is a hardware address, which means that it is stored in the firmware of the Network Interface Card (NIC).

A MAC address is globally unique. Each network card vendor gets its share of addresses (represented by the first 24 bits).

The address is written in the form of 12 hexadecimal digits. For example, consider the following MAC address:

C4-C6-85-EB-12-6C

Every hexadecimal character represents 4 bits, so the first six hexadecimal characters represent the vendor.

How to find out your own MAC address?

For Windows PC enter the Command Prompt (Ctl+R and write cmd and press enter). Type the ipconfig/all command and you will see a line called Physical address under the Ethernet adapter settings:

Mac Address of Windows

For Linux PC run Command Terminal and Type ifconfig then you can see you PC's MAC Address. You should see your MAC address referred to as HWaddress.

Mac Address of Linux

What is ip address?

An IP address is a product of modern computer technology designed to allow one computer (or other digital device) to communicate with another computer via the Internet. IP addresses allow the location of literally billions of digital devices that are connected to the Internet to be pinpointed and differentiated from other devices. In the manner sense that someone needs your mailing address to send you a letter, a remote computer needs your IP address to communicate with your computer.

How to find out your IP address?

Windows users:

Enter the Command Promt (Clt+R and Type cmd). Enter ipconfig. You should see a field called IP address. 

How to find IP address in Windows

Linux users:
Enter ifconfig. You should see a field called inet addr: 

How to find IP address in Linux

Ethernet Frame Sort Details

Ethernet Frame

An Ethernet frame contains the following fields:

 

Ethernet Frame CCNA Tutorials

 

The preamble is fifty six bits of alternating 1s and 0s that synchronizes communication on an local area network . it's followed by AN 8-bit begin of frame delimiter (10101011) that indicates a sound frame is close to begin. The preamble and therefore the begin of frame aren't thought-about a part of the particular frame, or calculated as a part of the whole frame size

Ethernet uses the 48-bit MAC address for hardware addressing. the primary 24-bits of a MAC address verify the manufacturer of the network interface, and therefore the last 24-bits unambiguously establish the host.