Net-Practice

a System Administration related exercise

What Is TCP/IP?

Transmission Control Protocol/Internet Protocol (TCP/IP) is a protocol system—a collection of protocols that supports network communications.

• TCP/IP carefully defines how information moves from sender to receiver. First, application programs send messages or streams of data to one of the Internet Transport Layer Protocols, either the User Datagram Protocol (UDP) or the Transmission Control Protocol (TCP). These protocols receive the data from the application, divide it into smaller pieces called packets, add a destination address, and then pass the packets along to the next protocol layer, the Internet Network layer.
• The Internet Network layer encloses the packet in an Internet Protocol (IP) datagram, puts in the datagram header and trailer, decides where to send the datagram (either directly to a destination or else to a gateway), and passes the datagram on to the Network Interface layer.
• The Network Interface layer accepts IP datagrams and transmits them as frames over a specific network hardware, such as Ethernet or Token-Ring networks.

Network

A network is a collection of computers or computer-like devices that can communicate across a common transmission medium. Often the transmission medium is an insulated metal wire that carries electrical pulses between the computers, but the transmission medium could also be a phone line, or even no line at all in the case of a wireless network.

Network protocol

A network protocol is a system of common rules that helps define the complex process of network communication. Protocols guide the process of sending data from an application on one computer, through the networking components of the operating system, to the network hardware, across the transmission medium, and up through the destination computer’s network hardware and operating system to a receiving application

Routing

A router is a special device that can read logical addressing information and direct data across the network to its destination. At the simplest level, a router divides a local subnet from the larger network.

IP Addressing

An IP address is a 32-bit binary address. This 32-bit address is subdivided into four 8-bit segments called octets. Humans do not work well with 32-bit binary addresses or even 8-bit binary octets, so the IP address is almost always expressed in what is called dotted-decimal format. In dotted-decimal format, each octet is given as an equivalent decimal number. The four decimal values (4 × 8 = 32 bits) are then separated with periods. Eight binary bits can represent any whole number from 0 to 255, so the segments of a dotted-decimal address are decimal numbers from 0 to 255. You have probably seen examples of dotted-decimal IP addresses on your computer, in this book, or in other TCP/IP documents. A dotted-decimal IP address looks like this: 209.121.131.14.

• Part of the IP address is used for the network ID, and part of the address is used for the host ID. As you learned earlier , the original scheme for specifying the network and host ID is through a system of address classes. Although the more recent CIDR classless addressing has reduced the importance of the class system, address classes are still important enough to describe here as a starting point for understanding addressing in TCP/IP.

Logical Addressing :

• A network adapter has a unique physical address. In the case of ethernet, the physical address (which is sometimes called a Media Access Control [MAC] address) used to be assigned to the adapter at the factory, although many contemporary devices now provide a means for changing the physical address. On a LAN, low-lying hardware-conscious protocols deliver data across the physical network using the adapter’s physical address. There are many network types, and each has a different way of delivering data. On a basic ethernet network, for example, a computer sends messages directly onto the transmission medium. The network adapter of each computer listens to every transmission on the local network to determine whether a message is addressed to its own physical address.

• On large networks, of course, every network adapter can’t listen to every message. (Imagine your computer listening to every piece of data sent over the Internet.) As the transmission medium becomes more populated with computers, a physical addressing scheme cannot function efficiently. Network administrators often segment networks using devices such as routers to reduce network traffic. On routed networks, administrators need a way to subdivide the network into smaller subnetworks (called subnets), and impose a hierarchical design so that a message can travel efficiently to its destination. TCP/IP provides this subnetting capability through logical addressing. A logical address is an address configured through the network software. In TCP/IP, a computer’s logical address is called an IP address. As you learn “The Internet Layer,” “Subnetting and CIDR,” an IP address can include X A network ID number identifying a network X A subnet ID number identifying a subnet on the network X A host ID number identifying the computer on the subnet The IP addressing system also lets the network administrator impose a sensible numbering scheme on the network so that the progression of addresses reflects the internal organization of the network.

Address Class:

A classification system for IP addresses. The network class determines how the address is subdivided into a network ID and host ID.

Subnet Mask

• Like an IP address, a subnet mask is a 32-bit binary number. The bits of the subnet mask are arranged in a pattern that reveals the subnet ID of the IP address to which the mask is associated. Figure 5.3 shows an IP address/subnet mask pair. Each bit position in the subnet mask represents a bit position in the IP address. The subnet mask uses a 1 for every bit in the IP address that is part of the network ID or subnet ID. The subnet mask uses a 0 to designate any bit in the IP address that is part of the host ID. You can think of the subnet mask as a map used for reading the IP address.

Resources

• Networking With Microsoft Tcp/Ip: Certified Administrator's Resource Edition Har/Cdr Edition by Drew Heywood and Rob Scrimger
• Sams teach yourself TCP/IP in 24 hours Book by Joe Casad
• TCP/IP network administration Book by Craig Hunt
• https://www.open.edu/openlearncreate/mod/oucontent/view.php?id=129584&printable=1
• https://github.com/ifanzilka/NetPractice
• https://velog.io/@mseo/NetPractice-과제-해석
• https://velog.io/@mseo/NetPractice-과제를-위한-기초학습
• https://m.blog.naver.com/PostView.naver?isHttpsRedirect=true&blogId=dreamxpeed&logNo=221671848467
• https://note.com/syamashi/n/n57fc506e0c5c
• https://www.ibm.com/docs/en/aix/7.1?topic=protocol-tcpip-protocols
• https://www.freecodecamp.org/news/subnet-cheat-sheet-24-subnet-mask-30-26-27-29-and-other-ip-address-cidr-network-references/
• https://www.coursera.org/learn/computer-networking/lecture/vdyzA/subnet-masks
• https://hackr.io/blog/subnet-cheat-sheet
• https://bigpel66.oopy.io/library/42/inner-circle/2
• https://www.youtube.com/watch?v=Mcahg0UqYSI&ab_channel=LearnToCode-الدارجةالمغربية
• https://www.youtube.com/watch?v=Mcahg0UqYSI&ab_channel=LearnToCode-الدارجةالمغربية
• https://www.youtube.com/watch?v=Mcahg0UqYSI&ab_channel=LearnToCode-الدارجةالمغربية
• https://www.youtube.com/watch?v=Mcahg0UqYSI&ab_channel=LearnToCode-الدارجةالمغربية