Security Considerations - ZyXEL Communications P-3202HN-Ba User Manual

Chapter 12 Firewalls
12.5 Technical Reference
This section provides some technical background information about the topics
covered in this chapter.
12.5.1 Guidelines For Enhancing Security With Your Firewall
Change the default password via web configurator.
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Think about access control before you connect to the network in any way.
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Limit who can access your router.
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Don't enable any local service (such as telnet or FTP) that you don't use. Any
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enabled service could present a potential security risk. A determined hacker might
be able to find creative ways to misuse the enabled services to access the firewall
or the network.
For local services that are enabled, protect against misuse. Protect by configuring
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the services to communicate only with specific peers, and protect by configuring
rules to block packets for the services at specific interfaces.
Protect against IP spoofing by making sure the firewall is active.
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Keep the firewall in a secured (locked) room.
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12.5.2 Security Considerations

Note: Incorrectly configuring the firewall may block valid access or introduce security
risks to the IAD 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?
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For example, if IRC 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
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for all users, will 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
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security 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.
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IAD User's Guide