Chapter 19 Firewall

Note: At the time of writing the ZyWALL’s VPN and GRE tunnels support IPv4 traffic so

IPv6 firewall rules do not apply to IPSec, SSL VPN, and GRE tunnel traffic.

Table 97 Example Firewall Behavior

FROM ZONE TO ZONEBEHAVIOR

From any to ZyWALL

DHCP traffic from any interface to the ZyWALL is allowed.

 

DHCPv6 and Default_Allow_ICMPv6_Group traffic from any interface to the

 

ZyWALL is allowed.

 

 

From LAN to any (other than

Traffic from the LAN to any of the networks connected to the ZyWALL is

the ZyWALL)

allowed.

 

 

From DMZ to WAN

Traffic from the DMZ to the WAN is allowed.

 

 

From IPSec VPN to any (other

Traffic from the IPSec VPN zone to any of the networks connected to the

than the ZyWALL)

ZyWALL is allowed.

 

 

From SSL VPN to any (other

Traffic from the SSL VPN zone to any of the networks connected to the

than the ZyWALL)

ZyWALL is allowed.

 

 

From TUNNEL to any (other

Traffic from the TUNNEL zone to any of the networks connected to the

than the ZyWALL)

ZyWALL is allowed.

 

 

From LAN to ZyWALL

Traffic from the LAN to the ZyWALL itself is allowed.

 

 

From DMZ to ZyWALL

DNS and NetBIOS traffic from the DMZ to the ZyWALL itself is allowed.

 

 

From WAN to ZyWALL

The default services listed in To-ZyWALL Rules on page 266 are allowed from

 

the WAN to the ZyWALL itself. All other WAN to ZyWALL traffic is dropped.

 

 

From IPSec VPN to ZyWALL

Traffic from the IPSec VPN zone to the ZyWALL itself is allowed.

 

 

From SSL VPN to ZyWALL

Traffic from the SSL VPN zone to the ZyWALL itself is allowed.

 

 

From TUNNEL to ZyWALL

Traffic from the TUNNEL zone to the ZyWALL itself is allowed.

 

 

From any to any

Traffic that does not match any firewall rule is dropped. This includes traffic

 

from the DMZ or WAN to any of the networks behind the ZyWALL and traffic

 

other than DNS and NetBIOS from the DMZ to the ZyWALL.

 

This also includes traffic to or from interfaces or VPN tunnels that are not

 

assigned to a zone (extra-zone traffic).

 

 

To-ZyWALL Rules

Rules with ZyWALL as the To Zone apply to traffic going to the ZyWALL itself. By default:

The firewall allows only LAN, WLAN, or WAN computers to access or manage the ZyWALL.

The ZyWALL allows DHCP traffic from any interface to the ZyWALL.

The ZyWALL allows DHCPv6 and Default_Allow_ICMPv6_Group traffic from any interface to the ZyWALL.

The ZyWALL drops most packets from the DMZ zone to the ZyWALL itself and generates a log except for DNS and NetBIOS traffic.

The ZyWALL drops most packets from the WLAN zone to the ZyWALL itself and generates a log except for BOOTP_SERVER, HTTP, HTTPS, and DNS traffic.

The ZyWALL drops most packets from the WAN zone to the ZyWALL itself and generates a log except for AH, ESP, GRE, HTTPS, IKE, NATT (NATT applies to IPv4 only), and VRRP traffic.

When you configure a firewall rule for packets destined for the ZyWALL itself, make sure it does not conflict with your service control rule. See Chapter 37 on page 443 for more information about service control (remote management). The ZyWALL checks the firewall rules before the service control rules for traffic destined for the ZyWALL.

266

 

ZyWALL 110/310/1100 Series User’s Guide