Final answer:
In a SIPR C2 Node, a firewall or an intrusion prevention system performs security roles such as IP blocks, signature blocks, and application whitelisting.
Step-by-step explanation:
The component that performs roles such as IP blocks, signature blocks, and application whitelisting within SIPR C2 Node is typically a security feature known as a firewall or an intrusion prevention system (IPS). The firewall acts as a barrier between trusted and untrusted networks, controlling the incoming and outgoing network traffic based on predetermined security rules. IP blocking is used to restrict access to or from particular IP addresses. Signature blocks are part of intrusion detection and prevention systems, which use known patterns to detect malicious activity. Application whitelisting is a security approach that allows only pre-approved software to run, blocking all other applications, which helps to protect against malware.