Question: What action should a GGSN take upon detecting a UE transmitting an IP packet with a spoofed source IP address, according to security standards for protecting access to IP-based services?
Option 1: Forward the packet but alert adjacent network elements of potential spoofing.
Option 2: Drop the packet and optionally log the event based on operator configuration against subscriber information (IMSI/MSISDN).
Option 3: Modify the source IP address to match the one assigned during PDP context activation before forwarding.
Option 4: Respond with an error message to the UE, indicating spoofing detection without taking further action.
Explanation: To protect against IP address spoofing and maintain network security, a GGSN must prevent packets with falsified source IP addresses from propagating. Dropping the packet immediately halts the potential security threat. Logging the event (with subscriber information like IMSI/MSISDN, if configured by the operator) aids in monitoring and responding to security incidents, aligning with robust security practices for securing access to IP-based services.