Hack the box - Introduction to networking module detailed Chinese tutorial

Explanation of basic network knowledge

Some basic knowledge about network , Learn and understand some network protocols , Network transmission , Network topology , And other related network knowledge

Catalog

Network structure ... 2

1.1 The type of network ... 2

1.2 Basic types of network topology ... 2

1.3 Basic classification of agents ... 4

1.4 Network model classification ... 5

network address ... 5

2.1IPV4 Address ... 5

2.2MAC Address ... 6

2.4 IPV6 Address ... 7

 

Network structure

1.1 The type of network

Wide area network （WAN）：            The traditional Internet

LAN （LAN）：              Internal network , For example, office network , Home networking

WLAN （WLAN）：  adopt WIFI Connected LAN

Virtual professional network （VPN）： Connect multiple networks to a LAN

 

1.2 Basic types of network topology

1.3 Basic classification of agents

Forward agency ：     Users send packets through the browser , Through the proxy server , Send data to... Through proxy server web The server

Reverse proxy ：     Filtering user input , for example web Firewall is a kind of reverse proxy

 

1.4 Network model classification

OSI Model:       Used to describe and define the communication between systems , altogether 7 layer , Each layer has specific functions

TCP/IP：           General network protocol , The most basic protocol of the Internet , Network data transmission, etc

 

Tip: relative TCP/IP Agreement for ,OSI Model Relatively outdated , There are many limitations , During transmission , Will encapsulate a head Header into packet ,head Save some information such as the identity of this packet

 

network address

2.1IPV4 Address

IPV4 Address by 32 Bit binary number means , Connect by points ,IP The address is divided into network part（ Network part ）,host part（ The host part of the ）, Divided by subnet mask（ Subnet mask to determine the location of the partition ）

 

Broadcast（ Broadcast address ）: the last one IPV4 The address of is the broadcast address

 

CIDR:        IP Mixed form of address and subnet mask , for example ：127.0.0.1/24    /24 Represents the subnet mask of binary representation 1 Number of digits , The subnet mask can be calculated

 

Subnet:    subnet , Yes, it will IP The address range is divided into smaller addresses , This allows you to allocate addresses to hosts under this network segment

 

Subnet Structure ：

                                                        Network address

                                                        Broadcast address

                                                        First host

                                                        Last host

                                                        Number of hosts

 

Subnet The distribution of ：                       We know one IP Address of the network part and host part The division of parts is based on subnet mask To divide , Examples are as follows , To illustrate a IP The process of address subnet division

 

example ： Suppose a IP Address ,192.168.12.160/26 Now it needs to be divided into 4 Subnet , What is the result after division ?

 

First step ： Divide first network part and host part According to the subnet mask , as follows

According to the given ip The subnet mask of the address can be calculated as :255.255.255.192

 

 

 

The binary representation is as follows ：

 

IPv4         1100 0000      1010 1000       0000 1100       1010 0000       192.168.12.160/26

Subnet mask  1111 1111      1111 1111       1111 1111       1100 0000       255.255.255.192

 

According to the subnet mask division ,host part by ：10 0000

Subnet network address Is to put host part Set all 0 , Available 192.168.12.128/26

Subnet boracast address Is to put host part Set all 1, Available 192.168.12.191

Then we can calculate the allocable IP Address of the HOST The number of 192-128+1 = 64

The distribution of IPV4 The range of addresses is 192.168.12.129-192.168.12.190（ Because the above two addresses have been assigned ）

 

The second step ： Divide subnets , as follows

Because we need to divide 4 Subnet ,4 be equal to 2^2, So we need to /26+2 = /28

 

Tip:2^n= Number of subnets divided

 

The binary representation is as follows ：

 

IPv4         1100 0000      1010 1000       0000 1100       1000 0000       192.168.12.128/28

Subnet mask  1111 1111      1111 1111       1111 1111       1111 0000       255.255.255.240

 

We calculated the current allocable HOST The total number is 64 , Now it is divided into 4 Subnet , We

 

You can calculate how many subnets there are HOST,64/4=16

 

The final results are as follows ：

 

Subnet No.	Network Address	First Host	Last Host	Broadcast Address	CIDR
1	192.168.12.128	192.168.12.129	192.168.12.142	192.168.12.143	192.168.12.128/28
2	192.168.12.144	192.168.12.145	192.168.12.158	192.168.12.159	192.168.12.144/28
3	192.168.12.160	192.168.12.161	192.168.12.174	192.168.12.175	192.168.12.160/28
4	192.168.12.176	192.168.12.177	192.168.12.190	192.168.12.191	192.168.12.176/28

 

 

2.2MAC Address

MAC Address ：                      It is from 48 Bit binary number composition ,MAC The address is physically connected , for example , bluetooth , Wireless network, etc , Altogether 6 position 16 A decimal number means , as follows ：

 

E:AD:BE:EF:13:37

DE-AD-BE-EF-13-37

DEAD.BEEF.1337

2.4 IPV6 Address

IPV6 Address ：    By 128 Bit binary number means , With 16 In hexadecimal form , as follows ：

 

Long ：fe80:0000:0000:0000:dd80:b1a9:6687:2d3b/64

short ：fe80::dd80:b1a9:6687:2d3b/64