Security Considerations - ZyXEL Communications FMG3024-D10A Series User Manual

Chapter 13 Firewall

13.6.2 Security Considerations

Note: Incorrectly configuring the firewall may block valid access or introduce security
risks to the Device and your protected network. Use caution when creating or
deleting firewall rules and test your rules after you configure them.
Consider these security ramifications before creating a rule:
Does this rule stop LAN users from accessing critical resources on the Internet? For example, if IRC
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is blocked, are there users that require this service?
Is it possible to modify the rule to be more specific? For example, if IRC is blocked for all users, will
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a rule that blocks just certain users be more effective?
Does a rule that allows Internet users access to resources on the LAN create a security
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vulnerability? For example, if FTP ports (TCP 20, 21) are allowed from the Internet to the LAN,
Internet users may be able to connect to computers with running FTP servers.
Does this rule conflict with any existing rules?
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Once these questions have been answered, adding rules is simply a matter of entering the
information into the correct fields in the web configurator screens.
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