Chapter 11 Interfaces

because it is a point-to-point interface. For these interfaces, you can only enter the IP address.

In many interfaces, you can also let the IP address and subnet mask be assigned by an external DHCP server on the network. In this case, the interface is a DHCP client. Virtual interfaces, however, cannot be DHCP clients. You have to assign the IP address and subnet mask manually.

In general, the IP address and subnet mask of each interface should not overlap, though it is possible for this to happen with DHCP clients.

In the example above, if the ZyWALL gets a packet with a destination address of 5.5.5.5, it might not find any entries in the routing table. In this case, the packet is dropped. However, if there is a default router to which the ZyWALL should send this packet, you can specify it as a gateway in one of the interfaces. For example, if there is a default router at 200.200.200.100, you can create a gateway at 200.200.200.100 on ge2. In this case, the ZyWALL creates the following entry in the routing table.

Table 71 Example: Routing Table Entry for a Gateway

IP ADDRESS(ES)

DESTINATION

0.0.0.0/0

200.200.200.10

 

0

 

 

The gateway is an optional setting for each interface. If there is more than one gateway, the ZyWALL uses the gateway with the lowest metric, or cost. If two or more gateways have the same metric, the ZyWALL uses the one that was set up first (the first entry in the routing table). In PPPoE/PPTP interfaces, the other computer is the gateway for the interface by default. In this case, you should specify the metric.

If the interface gets its IP address and subnet mask from a DHCP server, the DHCP server also specifies the gateway, if any.

Interface Parameters

The ZyWALL restricts the amount of traffic into and out of the ZyWALL through each interface.

•Egress bandwidth sets the amount of traffic the ZyWALL sends out through the interface to the network.

•Ingress bandwidth sets the amount of traffic the ZyWALL allows in through the interface from the network.1

1.At the time of writing, the ZyWALL does not support ingress bandwidth management.

 

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ZyWALL USG 50 User’s Guide