Security In General - ZyXEL Communications ZyXEL ZYWALL10 User Manual

ZyWALL 10 Internet Security Gateway
2. Think about access control before you connect a console port to the network in any way, including
attaching a modem to the port. Be aware that a break on the console port might give unauthorized
individuals total control of the firewall, even with access control configured.
3. Limit who can telnet into your router.
4. 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.
5. 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.
6. Protect against IP spoofing by making sure the firewall is active.
7. Keep the firewall in a secured (locked) room.

13.5.1 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.
1. 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!
2. 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.
3. Never give out a password or any sensitive information to an unsolicited telephone call or e-mail.
4. Never e-mail sensitive information such as passwords, credit card information, etc.,without encrypting
the information first.
5. Never submit sensitive information via a web page unless the web site uses secure connections. You can
identify a secure connection by looking for a small "key" icon on the bottom of your browser (Internet
Explorer 3.02 or better or Netscape 3.0 or better). If a web site uses a secure connection, it is safe to
submit information. Secure web transactions are quite difficult to crack.
6. Never reveal your IP address or other system networking information to people outside your company.
7. Be careful of files e-mailed to you from strangers. One common way of getting BackOrifice on a system
is to include it as a Trojan horse with other files.
13-10 What Is a Firewall?