Question: What security measure is **recommended** for the interface between the Mediation Function (MF) and the Law Enforcement Monitoring Facility (LEMF) to protect against address spoofing in a 3GPP-compliant lawful interception setup?
Option 1: Implementing Transport Layer Security (TLS) for encryption
Option 2: Utilizing a Virtual Private Network (VPN) for secure tunneling
Option 3: Enforcing strict firewall rules on the MF's destination IP address
Option 4: Deploying Internet Protocol Security (IPSec) between the MF and LEMF
Explanation: IPSec is specifically recommended to counter security threats such as address spoofing by providing authentication and encryption at the internet layer, ensuring the integrity and confidentiality of data exchanged between the Mediation Function (MF) and the Law Enforcement Monitoring Facility (LEMF) in a lawful interception context.