ZyXEL Communications ZYWALL USG 2000 Support Notes page 209

H. Firewall FAQ
H01. Why doesn't my LAN to WAN or WAN to LAN rule work?
There may be some reasons why firewall doesn't correctly constrain the access.
1. The WAN zone doesn't include all WAN interfaces. For example, if you create a PPPoE
interface, you need to add this ppp interface into the WAN zone.
2. The firewall rules order is not correct. Since firewall search firewall rules in order, it
will apply the first firewall rule that matches criteria.
H02. Why does the intra-zone blocking malfunction after I disable the firewall?
Intra-zone blocking is also a firewall feature. If you want to have intra-zone blocking working,
please keep the firewall enabled.
H03. Can I have access control rules to the device in firewall?
If your ZYWALL USG 2000 image is older than b6, the answer is No. Firewall only affects
the forwarded traffic. You need to set the access control rules in system for each service such
as DNS, ICMP, WWW, SSH, TELNET, FTP and SNMP. After b6 image, user can configure
to-ZyWALL rules to manage traffic that is destined to ZyWALL.
All contents copyright (c) 2008 ZyXEL Communications Corporation.
ZyWALL USG 2000 Support Notes
209