Network-based IDS

The network-based intrusion detection system monitors both the LAN
and WLAN in an effort to examine every single packet of traffic as it is
transmitted across the network. The idea is to ensure that this traffic
matches any known (preprogrammed) attack signature that might indicate
a hacker type of attack.

The most common type of attack is the denial of service (DoS) attack,
in which a hacker bombards the wireless network with so many packets
that literally no other traffic can flow across the network. The idea is
that if the hacker can’t access any of the network resources, nobody can.
A good NIDS will understand this type of attack pattern and then
summarily disconnect the network session from which these incoming
packets originate. The IDS will also send an immediate alert to the
administrator so that the administrator can take immediate action to
prevent any damage.