Computer Virus Infection And Prevention; Introduction To The Prestige Anti-Virus Packet Scan; Figure 14-1 Anti-Virus Packet Scan Example - ZyXEL Communications Prestige 662HW Series User Manual

Prestige 662HW Series User's Guide

14.2.1 Computer Virus Infection and Prevention

The follow describes a simplistic life cycle of a computer virus.
A computer gets a copy of a virus from an unknown source (such as the Internet, e-mail or
1.
removable storage media). The virus is harmless until the execution of an infected program.
The virus spreads to other files and programs on the computer.
2.
The infected files are unintentionally sent to another computer thus starting the spread of the virus.
3.
Once the virus is spread through the network, the number of infected networked computers can
4.
grow exponentially.
To prevent the spread of viruses, you need to install host-based anti-virus software on a computer
5.
or buy an anti-virus system like the Prestige.

14.3 Introduction to the Prestige Anti-virus Packet Scan

The Prestige has an integrated signature-based anti-virus packet scan. Set up the Prestige between your
local network and the Internet. This way the Prestige can scan the traffic transmitting between your
local network and the Internet. This eliminates the need to install the scanning engine and the pattern
file on every network computer and the administrative task of periodically updating the pattern file.
Your Prestige is able to scan network traffic (mail, web and FTP) for viruses.
14.3.1 How the Prestige Virus Scan Works
The following describes the virus scanning process on the Prestige.
The Prestige first identifies the packet types (SMTP, POP3, HTTP and FTP) from the network
1.
traffic.
If the packets are not session connection setup packets (such as SYN, ACK and FIN), the Prestige
2.
records the sequence of the packets.
The scanning engine scans the content of the packet for viruses.
3.
If a virus pattern is matched, the Prestige deletes the infected packets by cleaning the virus from the
4.
packet content before transmission and alerts the computer user(s).
14.3.2 Limitations of the Prestige Packet Scan
The scanning engine does not scan the following types of file for viruses
♦ Compressed or zipped files
14-2

Figure 14-1 Anti-virus Packet Scan Example

Anti-Virus Packet Scan