Before You Begin - ZyXEL Communications NXC5200 User Manual

If the packets are not session connection setup packets (such as SYN, ACK and
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FIN), the NXC records the sequence of the packets.
The scanning engine checks the contents of the packets for virus.
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If a virus pattern is matched, the NXC removes the infected portion of the file
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along with the rest of the file. The un-infected portion of the file before a virus
pattern was matched still goes through.
If the send alert message function is enabled, the NXC sends an alert to the file's
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intended destination computer(s).
Note: Since the NXC erases the infected portion of the file before sending it, you may
not be able to open the file.
Notes About the NXC Anti-Virus
The following lists important notes about the anti-virus scanner:
The NXC anti-virus scanner can detect polymorphic viruses.
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When a virus is detected, an alert message is displayed in Microsoft Windows
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computers. Refer to the
not display the alert messages.
Changes to the NXC's anti-virus settings affect new sessions (not the sessions that
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already existed before you applied the changed settings).
The NXC does not scan the following file/traffic types:
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• Simultaneous downloads of a file using multiple connections. For example,
when you use FlashGet to download sections of a file simultaneously.
• Encrypted traffic. This could be password-protected files or VPN traffic where
the NXC is not the endpoint (pass-through VPN traffic).
• Traffic through custom (non-standard) ports. The only exception is FTP traffic.
The NXC scans whatever port number is specified for FTP in the ALG screen.
• ZIP file(s) within a ZIP file.

20.1.3 Before You Begin

• Before using anti-virus, see
anti-virus service.
• You may need to customize the zones (in the Network > Zone) used for the
anti-virus scanning direction.
NXC5200 User's Guide
Appendix C on page 617
Chapter 8 on page 151
Chapter 20 Anti-Virus
if your Windows computer does
for how to register for the
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