ZyXEL Communications P-870HW-I Series, User Manual

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P-870HW-I1 User’s Guide
Chapter 11 Firewalls 153
3 The reply from the WAN goes to the ZyXEL Device.
4 The ZyXEL Device then sends it to the computer on the LAN in Subnet 1.
Figure 84 IP Alias
11.3 Guidelines for Enhancing Security with Your Firewall
• Change the default password via CLI (Command Line Interpreter) or web configurator.
• Limit who can telnet into your router.
• Don't enable any local service (such as SNMP or NTP) that you don't use. Any 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 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.
• Keep the firewall in a secured (locked) room.
11.3.1 Security In General
You can never be too careful! Factors outside your firewall, filtering or NAT can cause
security breaches. Below are some generalizations about what you can do to minimize them.
• Encourage your company or organization to develop a comprehensive security plan.
Good network administration takes into account what hackers can do and prepares
against attacks. The best defense against hackers and crackers is information. Educate all
employees about the importance of security and how to minimize risk. Produce lists like
this one!
• DSL or cable modem connections are “always-on” connections and are particularly
vulnerable because they provide more opportunities for hackers to crack your system.
Turn your computer off when not in use.
• Never give out a password or any sensitive information to an unsolicited telephone call or
e-mail.