Catalog

Use common network commands to obtain network information

One 、 utilize ipconfig Command to get local network information

1. effect

2. Part of the command usage  

Two 、 utilize ping Command to get remote network information

1. effect

2. principle

3、 ... and 、 Other common network commands  

1.nslookup command  

2.netstat command

 3.tracert command

 4.arp command

summary

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Use common network commands to obtain network information

         With the popularity of GUI Based Applications , Ordinary users have gradually forgotten DOS The era can only rely on the way of inputting commands and interacting with computers . But the command line still has its unique value , and Windows Some utilities are also available on the command line , It is especially suitable for sniffing and processing problems in the network .

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One 、 utilize ipconfig Command to get local network information

1. effect

  Displays the name of the network adapter in the computer IP Address , Subnet mask and default gateway .

2. Part of the command usage  

command	effect
ipconfig/all	Displays a complete list of all network adapters TCP/IP Configuration information
ipconfig/release	Release the current IP( For use by DHCP Automatic access to IP The situation of )
ipconfig/renew	Recapture IP( For use by DHCP Automatic access to IP The situation of )
ipconfig/displaydns	Displays the current host DNS Content in the cache
ipconfig/flushdns	Empty DNS cache

Two 、 utilize ping Command to get remote network information

1. effect

Check whether the network is unobstructed or the network connection speed  

2. principle

• ping Is based on ICMP Agreement working , Used ICMP Echo request in (echo request) And echo response (echo reply) message , The types are 8 and 0.
• On the network IP There is a unique certainty IP Address , We give the target IP Address to send a packet , The other party returns a packet of the same size , According to the returned packets, we can determine the existence of the target host , The operating system of the target host can be preliminarily determined .
• ping It can display the amount of time between sending a request and returning a response in milliseconds . If the response time is short , Indicates that the datagram does not pass through too many routers or networks , Fast connection speed .
• ping Can display TTL（Time To Live, Time to live ） value , adopt TTL The value can be used to calculate how many routers a packet has passed through .

 

3、 ... and 、 Other common network commands  

1.nslookup command  

         Used to view domain names and IP Correspondence of . It usually needs a domain name server to provide domain names . If the user has set up a domain name server , You can use this command to view the data of different hosts IP The domain name corresponding to the address .

for example ： adopt csdn Your domain name to see its IP

 

 

2.netstat command

         Used to view network status , You can understand the current state of the network .netstat The command can display the active TCP Connect 、 The port on which the computer listens 、 Ethernet statistics 、IP Routing table 、IPv4 Statistics （ about IP、ICMP、TCP and UDP agreement ） as well as IPv6 Statistics （ about IPv6、ICMPv6、 adopt IPv6 Of TCP as well as UDP agreement ）. If it is used without parameters ,netstat Show active TCP Connect .

  example ：

        netstat -n： In dotted decimal form IP Address , Instead of symbolic host names and network names .

          Approved above nslookup Ordered us to find csdn Of IP, So now you can visit the website in the browser www.hbfu.edu.cn, utilize netstat -n View the local network status , Is there anything about www.hbfu.edu.cn Website connection establishment

give the result as follows ：

 

 3.tracert command

          Track route information , Use this command to find out all the ways the data is transferred from the local machine to the target host , This is very helpful for us to understand the network layout and structure , If the network fails , You can use this command to see where the problem is .

 

  Among them, the output is 5 Column ： The first column is the second column describing the path n The number of jumps , That is, the router number along the path ; The second column is the first round trip delay ; The third column is the second round trip delay ; The fourth column is the third round trip delay ; The fifth column is the name of the router and its input port IP Address . If the source receives less than... Packets from any given router 3 strip （ Due to packet loss in the network ）,traceroute Put an asterisk after the router number , And report that less than 3 The first round trip time .

 4.arp command

          Use arp command , Be able to view the ARP The current content in the cache . Besides , Use arp The command can manually set the static physical address of the network card /IP The address of , In this way, you can make local static configuration for common hosts such as default gateway and local server , This helps to reduce the amount of information on the Internet .

• arp –a： Used to view all items in the cache . 

• arp –d： Delete all dynamic arp Table item .

• arp –d IP： Delete a static item .

• arp –s IP MAC： towards ARP Manually enter a static item in the cache . The project will remain valid during the computer boot process , Or when something goes wrong , The manually configured physical address will automatically update the project .

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summary

These are the functions of some common network commands and the methods of using them to obtain network information . For these network commands , Understand them and master their application skills , It is the basis of quickly and accurately judging network faults , It is also the basis of information security .