Prestige 2602H-6xC Support Notes
Why do you need a firewall when your router has packet filtering and NAT
With the spectacular growth of the Internet and online access, companies that do business on the Internet face greater security threats. Although packet filter and NAT restrict access to particular computers and networks, however, for the other companies this security may be insufficient, because packets filters typically cannot maintain session state. Thus, for greater security, a firewall is considered.
What is Denials of Service (DoS)attack?
Denial of Service (DoS) attacks are aimed at devices and networks with a connection to the Internet. Their goal is not to steal information, but to disable a device or network so users no longer have access to network resources.
There are four types of DoS attacks:
1.Those that exploits bugs in a TCP/IP implementation such as Ping of Death and Teardrop.
2.Those that exploits weaknesses in the TCP/IP specification such as SYN Flood and LAND Attacks.
3.
4.IP Spoofing
What is Ping of Death attack?
Ping of Death uses a 'PING' utility to create an IP packet that exceeds the maximum 65535 bytes of data allowed by the IP specification. The oversize packet is then sent to an unsuspecting system. Systems may crash, hang, or reboot.
What is Teardrop attack?
Teardrop attack exploits weakness in the reassemble of the IP packet fragments. As data is transmitted through a network, IP packets are often broken up into smaller chunks. Each fragment looks like the original packet except that it contains an offset field. The Teardrop program creates a series of IP fragments with overlapping offset fields. When these fragments are reassembled at the destination, some systems will crash, hang, or reboot.
What is SYN Flood attack?
SYN attack floods a targeted system with a series of SYN packets. Each packet causes the targeted system to issue a
119
All contents copyright (c) 2005 ZyXEL Communications Corporation.
