Network intrusion detection systems (NIDSs) which aim to identify various attacks, have become an essential part of current security infrastructure. In particular, signature-based NIDSs are being widely implemented in industry due to their low rate of false alarms. However, the signature matching process is a big challenge for these systems, in which the cost is at least linear to the size of an input string. As a result, overhead packets will be a major issue for practical usage, where the incoming packets exceed the maximum capability of an intrusion detection system (IDS). To mitigate this problem, packet filtration is a promising solution to reduce unwanted traffic. Motivated by this, in this work, a list-based packet filter was designed and an engineering method of combining both blacklist and whitelist techniques was introduced. To further secure such filters against IP spoofing attacks, a lightweight but efficient IP verification mechanism was developed. In the evaluation, a list-based packet filter was deployed in both simulated and real network environments under honest and dishonest scenarios. Experimental results demonstrate that the developed list-based packet filter is effective in traffic filtration as well as workload reduction, and is robust against IP spoofing attacks.