Chapter 19 Firewall
Your firewall would have the following configuration.
Table 85 Blocking All LAN to WAN IRC Traffic Example
# | USER | SOURCE | DESTINATIO | SCHEDULE | SERVICE | ACTION | |
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1 | Any | Any | Any | Any | IRC | Deny | |
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Default | Any | Any | Any | Any | Any | Allow | |
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•The first row blocks LAN access to the IRC service on the WAN.
•The second row is the firewall’s default policy that allows all traffic from the LAN to go to the WAN.
The ZyWALL applies the firewall rules in order. So for this example, when the ZyWALL receives traffic from the LAN, it checks it against the first rule. If the traffic matches (if it is IRC traffic) the firewall takes the action in the rule (drop) and stops checking the firewall rules. Any traffic that does not match the first firewall rule will match the default rule and the ZyWALL forwards it.
Now suppose that your company wants to let the CEO use IRC. You can configure a LAN to WAN firewall rule that allows IRC traffic from the IP address of the CEO’s computer. You can also configure a LAN to WAN rule that allows IRC traffic from any computer through which the CEO logs into the ZyWALL with his/her user name. In order to make sure that the CEO’s computer always uses the same IP address, make sure it either:
•Has a static IP address, or
•You configure a static DHCP entry for it so the ZyWALL always assigns it the same IP address (see Section 10.1.4 on page 182 for information on DHCP).
Now you configure a LAN to WAN firewall rule that allows IRC traffic from the IP address of the CEO’s computer (192.168.1.7 for example) to go to any destination address. You do not need to specify a schedule since you want the firewall rule to always be in effect. The following figure shows the results of your two custom rules.
Figure 184 Limited LAN to WAN IRC Traffic Example
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