Linux network mode and remote connection error troubleshooting

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1. Virtual software network mode

1. NAT network mode

• Features: virtual host and host network information can be inconsistent 10.0.3.x 10.0.0.x
• Advantages: IP address conflicts in the bureau and city network are not easy to occur
• Disadvantages: other hosts cannot directly access the virtual host

2. Bridge network mode

• Features: The network information of the virtual host and the host is the same 10.0.3.x 10.0.3.x
• Disadvantage: Prone to IP address conflicts in the LAN
• Advantages: other hosts can directly access the virtual host

3. Host only mode

• Features: The virtual host network can only establish communication with the host or other virtual hosts
• Disadvantage: can't even click on the external network
• Advantages: more secure

Second, remote connection troubleshooting

1. Smooth link

1.1. Check the smooth way: ping

1.2 Reasons for obstruction

• Physical line problem / physical host shutdown
• The network security device has turned off the ping function
• Whether the virtual host network card address is set correctly
• Whether the virtual network card (VMnet8) is turned on and set successfully
• Whether the virtual host network service is closed

2. Network security policy prevents access

• Whether the firewall is off
• SSH service configuration can also prevent users from connecting remotely

3. The remote service is not turned on

3.1, check

• Check if the remote service is turned on
• In the network, each network service is set with a digital number, called the network service port
  • SSH service port number: 22

3.2 Reasons for connection failure

• Remote service closed
  • systemctl start sshd
• The network card setting error in the virtual network editor
  • Simply restore by default
• Virtual software program is not running properly
  • Check whether the virtual software service is enabled --window standard+r--services.msc
  • Turn on or restart all services