**A log** is a record of events that occur within an organisation's systems and networks. Common log sources: - *Firewall log*: A record of attempted or established connections for incoming traffic from the internet. It also includes outbound requests to the internet from within the network. - *Network log*: A record of all computers and devices that enter and leave the network. It also records connections between devices and services on the network. - *Server log*: A record of events related to services such as websites, emails, or file shares. It includes actions such as login, password, and username requests.