P-660R-Tx v2 Series User’s Guide
Chapter 5 LAN Setup 52
Figure 16 Any IP Example
The Any IP feature does not apply to a computer using either a dynamic IP address or a static
IP address that is in the same subnet as the ZyXEL Device’s IP address.
Note: You must enable NAT/SUA to use the Any IP feature on the ZyXEL Device.
5.5.1 How Any IP Works
Address Resolution Protocol (ARP) is a protocol for mapping an Internet Protocol address (IP
address) to a physical machine address, also known as a Media Access Control or MAC
address, on the local area network. IP routing table is defined on IP Ethernet devices (the
ZyXEL Device) to decide which hop to use,
to help forward data along to its specified
destination.
The following lists out the steps taken, when a computer tries to access the Internet for the first
time through the ZyXEL Device.
1 When a computer (which is in a different subnet) first attempts to access the Internet, it
sends packets to its default gateway (which is not the ZyXEL Device) by looking at the
MAC address in its ARP table.
2 When the computer cannot locate the default gateway, an ARP request is broadcast on the
LAN.
3 The ZyXEL Device receives the ARP request and replies to the computer with its own
MAC address.
4 The computer updates the MAC address for the default gateway to the ARP table. Once
the ARP table is updated, the computer is able to access the Internet through the ZyXEL
Device.
5 When the ZyXEL Device receives packets from the computer, it creates an entry in the IP
routing table so it can properly forward packets intended for the computer.