Network Security Learning (II) IP address

Clone virtual machine

1. Click snapshot Manager

2. Choose Clone

next step

3. Select snapshot

4. Select the clone type

The linked clone is based on the original clone , If the original clone is deleted , Then link cloning cannot be used

Full cloning is equivalent to creating a new virtual machine

Link cloning is recommended

5. Specify virtual machine name , route

Can be completed

  Fundamentals of computer network

        LAN ： It's commonly known as the intranet

         The composition of simple LAN ： Switch 、 Ethernet cable 、PC（ Or others IT terminal ）

        Switch ： A device used to build a local area network for an intranet .

IP Address

IP An address is a unique identifier , It's a network code （ Binary system ）, from 32 A composition

Such as 11111111.11111111.11111111.11111111

Easy to remember （ Convert to 10 Base number ）

255.255.255.255

This representation is also known as dotted decimal

dotted decimal （Dotted Decimal Notation） The full name is point and minute （ Dot pattern ） Decimal notation , yes IPv4 Of IP Address identification method .IPv4 Four bytes are used to represent a IP Address , Each byte is expressed as 0~255. dotted decimal Just use 4 Group from 0~255 The number of , To represent a IP Address . Such as 192.168.1.1.

Subnet mask

LAN communication rules ： In the same LAN , be-all IP You must be in the same network segment to communicate with each other .

IP The composition of the address ： Network bit + Host bit （ The network bits are the same IP Address , For the same segment ）.

How the subnet mask determines the network bit : And 255 The corresponding number is network bit , And 0 The corresponding number is the host bit

 

Here's an additional explanation IP And operation of address and subnet mask
“ And ” Operation can find this IP Subnet of address , Or the network segment it is in .
for instance ：
IP: 192.168.1.160 subnet ：255.255.255.128

1100 0000.1010 1000. 0000 0001. 1010 0100
1111  1111. 1111 1111.  1111  1111. 1000 0000
------------------------------------------------ Meet each other （ All for 1 Then for 1, Otherwise 0）
1100 0000.1010 1000.0000 0001.1000 0000
Convert to decimal to ：192.168.1.128

IP Address details

classification

1、A class IP Address ：1-126

         One A class IP Address by 1 Byte network address and 3 Byte host address composition , The highest bit of the network address must be “0”, Address range from 1.0.0.0 To 126.0.0.0. Usable A There are 126 individual , Every network can hold 1 More than 100 million hosts .

2、B class IP Address ：128-196

         One B class IP Address by 2 Byte network address and 2 Byte host address composition , The highest bit of the network address must be “10”, Address range from 128.0.0.0 To 191.255.255.255. Usable B There are 16382 individual , Every network can hold 6 More than ten thousand hosts .

3、 C class IP Address ：192-223

         One C class IP Address by 3 Byte network address and 1 Byte host address composition , The highest bit of the network address must be “110”. Range from 192.0.0.0 To 223.255.255.255.C Class network up to 209 More than a , Every network can hold 254 Host computer .

4、 D class IP Address ：224-239

         The first byte is in “lll0” Start , It is a special door Reserved address . It doesn't point to a specific network , At present, this kind of address is used in multicast (Multicast) in . A multicast address is used to address a group of computers at a time , It identifies a group of computers that share the same protocol .

5、E class IP Address ： 240-254

          With “llll0” Start , Reserved for future use . All zeros (“0.0.0.0”) The address corresponds to the current host . whole “1” Of IP Address (“255.255.255.255”) Is the broadcast address of the current subnet .

stay win2003 Middle configuration ip Address

1. Right click on the Internet neighbor —— attribute

 

2. Right click local connection —— attribute

 3. double-click tcp/ip agreement , Manual configuration ip Address （ The server uses fixed ip Address ）

notes ： Do not blindly follow the picture ip Address configuration ！

 

see ip Address

1. Double click the local connection —— Support

 

127.0.0.1

127.0.0.1 It's the return address , The local machine , Generally used to test the use of . Return address （127.x.x.x） It's the local loopback address （Loopback Address）, I.e. mainframe IP Inside the stack ip Address , It is mainly used for network software testing and local computer , No matter what interprocess communication program , Once the data is sent using the return address , The protocol software immediately returns , No network transmission .

experiment

1. Turn on two virtual machines , Change the configuration to the setting in the figure

  Among them, custom VMent Out of commission 0

2. Turn off the system firewall

Off by default

3. Set up the computer manually ip Address , Make it in the same network segment

 

4. Using the command line ping Command test （win + R—— Input cmd）

 

  Some test commands

1. View network information

ipconfig                    # see IP The basic information of the address 
ipconfig /all               # see IP Address details 

 2. Test network connectivity

ping  The goal is ip Address              # Test network connectivity , You can communicate whenever you go back , Default send 4 A package 
ping -t  The goal is ip Address           # Send test packages continuously 
ping -n  Number   The goal is ip Address      # Appoint ping The number of bags 
 

 3. Resolve the domain name manually

nslookup  domain name         # Resolve the domain name manually