ZyXEL Communications 100 Series, 200 Series manual 339

Chapter 19 Firewall

•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 LAN1, 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 LAN1 to WAN firewall rule that allows IRC traffic from the IP address of the CEO’s computer. You can also configure a LAN1 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 DHCP Settings on page 266 for information on DHCP).

Now you configure a LAN1 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 239 Limited LAN to WAN IRC Traffic Example

Your firewall would have the following configuration.

Table 111 Limited LAN to WAN IRC Traffic Example 1

#	USER	SOURCE	DESTINATION	SCHEDULE	SERVICE	ACTION
1	Any	192.168.1.7	Any	Any	IRC	Allow
2	Any	Any	Any	Any	IRC	Deny
Default	Any	Any	Any	Any	Any	Allow

•The first row allows the LAN1 computer at IP address 192.168.1.7 to access the IRC service on the WAN.

•The second row blocks LAN access to the IRC service on the WAN.

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ZyWALL USG 100/200 Series User’s Guide