Figure 100 limited lan to wan irc traffic example, Table 41 limited lan to wan irc traffic example – ZyXEL Communications NBG410W3G User Manual
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Chapter 9 Firewall
NBG410W3G Series User’s Guide
172
The ZyXEL Device applies the firewall rules in order. So for this example, when the ZyXEL
Device 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
ZyXEL Device 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. 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 ZyXEL Device always assigns it the
same IP address (see
for information on static 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 100 Limited LAN to WAN IRC Traffic Example
Your firewall would have the following configuration.
• The first row allows the LAN 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.
• The third row is (still) the firewall’s default policy of allowing all traffic from the LAN to
go to the WAN.
The rule for the CEO must come before the rule that blocks all LAN to WAN IRC traffic. If the
rule that blocks all LAN to WAN IRC traffic came first, the CEO’s IRC traffic would match
that rule and the ZyXEL Device would drop it and not check any other firewall rules.
Table 41 Limited LAN to WAN IRC Traffic Example
#
SOURCE
DESTINATIO
N
SCHEDULE
SERVICE
ACTION
1
192.168.1.7
Any
Any
IRC
Allow
2
Any
Any
Any
IRC
Drop
Default
Any
Any
Any
Any
Allow
LAN
192.168.1.7
CEO
WAN
IRC