Internal/External Interface; Internal/External Ethernet Add/Edit - ZyXEL Communications USG FLEX H Series User Manual

7.3 Internal/External Interface

Use this screen to configure the external interface settings for connecting to an external network (like
the Internet). The Zyxel Device automatically adds an external interface to the default WAN trunk.
Use this screen to configure the internal interface settings for connecting to a local network. Other
corresponding configuration options are DHCP server and DHCP relay. The Zyxel Device automatically
applies the default SNAT settings to traffic flowing from an internal interface to an external interface.

7.3.1 Internal/External Ethernet Add/Edit

Unlike other types of interfaces, you cannot create new Ethernet interfaces nor can you delete any of
them. If an Ethernet interface does not have any physical ports assigned to it, the Ethernet interface is
effectively removed from the Zyxel Device, but you can still configure it.
Ethernet interfaces are similar to other types of interfaces in many ways. They have an IP address, subnet
mask, and gateway used to make routing decisions. They restrict the amount of bandwidth and packet
size. They can provide DHCP services, and they can verify the gateway is available.
Use Ethernet interfaces to control which physical ports exchange routing information with other routers
and how much information is exchanged through each one. The more routing information is
exchanged, the more efficient the routers should be. However, the routers also generate more network
traffic, and some routing protocols require a significant amount of configuration and management.
Chapter 7 Interfaces
USG FLEX H Series User's Guide
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