How to resolve the issue of being unable to connect to the internet after setting up the IP address on CentOS 7?

If you are unable to connect to the internet after setting up the IP on CentOS 7, there could be several possible reasons:

1. Check the network configuration for errors, such as ensuring the correct IP address, subnet mask, gateway, and DNS server are set up properly. You can use commands like ‘ip addr show’ and ‘ip route show’ to view the current network configuration.
2. The network service is not running: Check if the network service has been started by using the command ‘systemctl status network’ to see the status of the network service. If the service is not running, you can start the network service by using the command ‘systemctl start network’.
3. Firewall configuration issue: If the firewall is enabled, it may block network connections. You can use the command systemctl status firewalld to check the status of the firewall. If the firewall is enabled, you can use the command systemctl stop firewalld to temporarily disable the firewall, or use the command systemctl disable firewalld to permanently disable the firewall.
4. Routing configuration issue: Check if the gateway and routing configurations are correct, you can use the command “ip route show” to view the current routing configuration. If there is a routing configuration error, you can use the command “ip route add” to add the correct routing.
5. DNS configuration issue: Verify if the DNS server settings are correct by editing the /etc/resolv.conf file. You can try using public DNS servers such as 8.8.8.8 and 8.8.4.4.

If the previous methods still cannot solve the problem, more detailed network debugging and troubleshooting may be necessary. You can try using the commands ping and traceroute to test network connectivity and routing, or check the system logs for more error information.