How does IP spoofing affect the defense against DDoS attacks on GTP servers, and what countermeasures can be employed?

IP spoofing allows attackers to disguise the origin of their traffic, making it difficult to identify and block malicious sources. Countermeasures include ingress filtering (validating source IP addresses at the network edge) and traceback mechanisms to help identify the true source of the attack. Also, using a DDoS mitigation service that can identify and filter spoofed packets can prove effective.