If you want to perform basic filtering on your network interface without a firewall, what should you establish?

To perform basic filtering on your network interface without the use of a firewall, establishing an IPSec policy is a valid approach. IPSec (Internet Protocol Security) is a suite of protocols designed to secure IP communications by authenticating and encrypting each IP packet of a communication session. By implementing an IPSec policy, you can create rules that determine which traffic is allowed or blocked based on factors such as source and destination IP addresses and protocols being used. This capability provides essential filtering functions at the network layer.

Establishing an IPSec policy allows for secure communications between devices, protecting the integrity and confidentiality of the data as it traverses the network without the need for a dedicated firewall. This makes it particularly effective for scenarios where a firewall may not be present.

In contrast, while a Virtual Private Network (VPN) is necessary for secure remote access, it primarily focuses on providing a secure connection rather than filtering traffic. Application Layer Filtering is more advanced and specifically inspects the data at the application layer, which may include mechanisms beyond basic traffic control. Network Address Translation (NAT) modifies the source or destination IP addresses of packets as they pass through a router and can help obscure internal network addressing but does not inherently provide filtering capabilities as defined in the context