ZyXEL Communications 3.1 User Manual

ZyWALL (ZLD) CLI Reference Guide

This chapter shows you how to use interface-related commands.

In general, an interface has the following characteristics.

• An interface is a logical entity through which (layer-3) packets pass.
• An interface is bound to a physical port or another interface.
• Many interfaces can share the same physical port.
• An interface is bound to at most one zone.
• Many interface can belong to the same zone.
• Layer-3 virtualization (IP alias, for example) is a kind of interface.

Some characteristics do not apply to some types of interfaces.

You can create several types of interfaces in the ZyWALL. The types supported vary by ZyWALL 
model.

• Port groups create a hardware connection between physical ports at the layer-2 (data link, MAC 

address) level.

• Ethernet interfaces are the foundation for defining other interfaces and network policies. RIP 

and OSPF are also configured in these interfaces.

• VLAN interfaces receive and send tagged frames. The ZyWALL automatically adds or removes 

the tags as needed. Each VLAN can only be associated with one Ethernet interface.

• Bridge interfaces create a software connection between Ethernet or VLAN interfaces at the 

layer-2 (data link, MAC address) level. Unlike port groups, bridge interfaces can take advantage 
of some security features in the ZyWALL. You can also assign an IP address and subnet mask to 
the bridge.

• PPPoE/PPTP interfaces support Point-to-Point Protocols (PPP). ISP accounts are required for 

PPPoE/PPTP interfaces.

• Cellular interfaces are for 3G WAN connections via a connected 3G device.
• WLAN interfaces are for wireless LAN (IEEE 802.11b/g) connections via an installed wireless 

LAN card.

• Virtual interfaces (IP alias) provide additional routing information in the ZyWALL. There are 

three types: virtual Ethernet interfaces, virtual VLAN interfaces, and virtual bridge 
interfaces.