How to resolve the issue of CentOS 7 configuration not taking effect on the routing table?

If the routing table configured on CentOS 7 is not taking effect, you can troubleshoot and resolve it by following these steps:

1. Confirm if the routing table is correctly configured by using the “ip route show” command to check the configured table, ensuring that the destination network and next hop address in the routing table are correct.
2. Check if the network interface is enabled: Use the “ip link show” command to check if the network interface is enabled and working properly. If the interface is not enabled, you can use the “ifup” command to enable it.
3. Check the default route settings: Use the command “ip route show default” to check if the default route is correctly set. If the default route is incorrect, you can use the command “ip route del default” to remove the incorrect default route, and then add the correct default route using “ip route add default via [next_hop] dev [interface]”.
4. Check firewall settings: If a firewall (such as firewalld) is enabled on the system, make sure that the configured routing table allows traffic to pass through the firewall. Use firewall commands (such as firewall-cmd) to add the necessary rules.
5. Restarting the network service: If the above steps have not resolved the issue, you can try restarting the network service by using the command systemctl restart network.

If the problem still persists, you can try updating the operating system or reaching out to the network administrator for further assistance and support.