In general, wireless devices are designed to operate in one of two modes, either Ad-Hoc or Infrastructure mode.

Wireless networks are typically identified by broadcasting a Service Set Identifier (SSID) and this is used during the authentication stages. In cases where a masked SSID is used, the connecting client also sends the unmasked SSID to the non-broadcasting network instead.

Ad-Hoc

This mode is also known as a peer-to-peer wireless network, think of wireless tether on a mobile device. It is created as a quick and easy way of sharing resources, in the case of mobile tether, the resource shared is typically a 4G mobile internet connection.

Infrastructure

With an infrastructure mode wireless network, there is typically a central access point. The access point creates and broadcasts the wireless network, ready for clients to connect and authenticate to.

A typical home network would have a single wireless access point, configured to allow internet connection sharing. This is known as a Basic Service Set configuration (BSS). In the corporate world, an organisation may have many access points, all with the same function of providing secured access to company assets such as email and file servers. This configuration is known as an Extended Service Set configuration, this is because it contains multiple access points connecting to a single wired network or Distribution System (DS).

Monitor

Monitor mode is not typically a wireless mode of operation.  The previous modes identified above, perform some level of filtering. When an adapter is placed into a monitor or promiscuous mode, filtering is disabled. This allows the adapter to receive or listen to raw data and packets, which is required for many of the tools we will be using in this course.