View existing hostname in Linux

[user1@localhost~]$hostname
localhost.localdomain
      

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Setup hostname for temporarily

[root@localhost~]#hostname Linux1.example.com

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View IP configuration

                                    
[root@Linux1~]#ifconfig
      

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Manually resolve hostname and IP address

[root@localhost~]#vi /etc/hosts
192.168.1.100 Linux1.example.com Linux1
      

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Setup Server IP address temporarily

[root@Linux1~]#ifconfig <network_device_name> <IP
address> netmask <netmask_value>
Example:
[root@Linux1~]#ifconfig enp1s7 192.168.1.100 netmask
255.255.255.0
      

Setup an IP address- Manual/Automatic

                                    
[root@Linux1~]#nmtui
Select Edit Connection
Select devices –Edit
Select Static (Manual method)
Configure IP Address ,Subnet Mask, DNS Server and
Default Gateway IP Address
Select Quit to proceed
      

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Restarting Network Service to apply new configuration

CentOS 7/RHEL 7

#service network restart
#systemctl start network
#systemctl enable network
      

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CentOS 8/9 RHEL 8/9

#systemctl start NetworkManager.service
#systemctl stop NetworkManager.service
#systemctl restart NetworkManager.service
#systemctl status NetworkManager.service
  

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Enable/disable Lan network

[root@Linux1~]#ifdown enp1s1
[root@Linux1~]#ifup enp1s1
[root@Linux1~]#ifconfig    
     

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Monitor network statistics

The ss (socket statistics) command is a powerful tool in Linux used for examining sockets. Socket = (TCP Port + IP Address)

[root@Linux1~]#ss –ta
   

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Display status of all network devices

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Display only Active connections