Network Intrusion Detection System (Nids); Nids Features; Denial Of Service (Dos) Attacks; Reconnaissance - D-Link DFL-500 User Manual

Network Intrusion detection system (NIDS)

The DFL-500 NIDS is a real-time network intrusion detection sensor that can identify a wide variety of
suspicious network traffic including direct attacks, and take action as required. The NIDS uses attack
signatures, stored in the attack database, to identify common attacks. In response to an attack, the NIDS
protects the DFL-500 and the networks connected to it by:
· Dropping the connection
·
Blocking packets from the location of the attack
·
Blocking network ports, protocols, or services being used by an attack
To notify system administrators of the attack, the NIDS sends alert e-mails to up to three system
administrators.
The attack database functions in a similar manner to an antivirus database. D-Link updates the attack
database periodically. You can download and install attack database updates manually (see
database updates). You can also configure the DFL-500 to automatically check for and download attack
database updates (see
This chapter describes:
·

NIDS features

·
Configuring NIDS detection
·
Viewing the attack list
·
Configuring NIDS responses
NIDS features
The NIDS protects the DFL-500 and the networks connected to it from the attacks described below:
·

Denial of Service (DoS) attacks

·

Reconnaissance

·
Exploits
·
NIDS evasion
Denial of Service (DoS) attacks
Denial of service attacks attempt to deny access to a service or a computer by overloading network links,
overloading the CPU, or filling up disks. The attacker is not trying to gain information, but is simply acting as a
vandal to prevent users from accessing their network resources. The DFL-500 NIDS protects against the
following common DoS attacks:
· Packet floods including Smurf flood, TCP SYN flood, UDP flood, and ICMP flood
·
Incorrectly formed packets including Ping of Death, Chargen, Tear drop, land, and WinNuke
Reconnaissance
Reconnaissance attacks attempt to gain information about a computer network in preparation for an attempt
to break into it. Using the information gained, an attacker can identify and attack specific vulnerabilities. The
DFL-500 NIDS protects against the following common reconnaissance attacks:
·
Fingerprinting
·
Ping Sweeps
·
Port Scans
DFL-500 User Manual
Automatic antivirus and attack database updates).
Manual attack
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