A stateless firewall filters traffic based on static values such as source and destination IP addresses, port numbers, and protocols. It does not have the ability to understand or determine the state of network connections, which differentiates it from stateful firewalls that can monitor the full state of active connections and make decisions based on the context of the traffic. Stateless firewalls are faster and less complex, but they are not as secure as stateful firewalls because they cannot understand the state of the network connections. A web application firewall (WAF) is designed to protect web applications by filtering and monitoring HTTP traffic, while a unified threat management (UTM) firewall is an advanced firewall that combines multiple security features into a single device. Network-based intrusion prevention systems (NIPS) monitor the network for malicious activities, which is not directly related to basic filtering rules based on static values.