What are the advantages and disadvantages of using Firewall iptables in the Linux Kernel for IP address blocking in PHP applications?

One way to block IP addresses in PHP applications is by using Firewall iptables in the Linux Kernel. This method allows for blocking IP addresses at the network level, providing an additional layer of security. However, it requires server-level access and configuration, which may not be feasible for all developers.

// Example code snippet for blocking an IP address using Firewall iptables in PHP
$ipAddress = "192.168.1.1";
exec("sudo iptables -A INPUT -s $ipAddress -j DROP");