Understand the processes used to determine security and performance problems. Log reviewing helps derive the root cause of a problem. Port scanning helps administrators verify ports are open in a firewall for a specific service. Nmap is a popular tool for port scanning of hosts and networks. Vulnerability scanning can include port scanning, but it is focused on detecting specific vulnerabilities. Patch management is used after a vulnerability is identified. Baselines should be reviewed for security and performance of network systems. Packet capture utilities such as Wireshark let us review traffic at the packet level. Traffic analysis tools allow the capturing of packets to deduce traffic patterns in network traffic.