Product specifications

Chapter 4: System Management Efficient Networks
®
Router family
Technical Reference Guide
Page 4-18 Efficient Networks
®
Masquerading
With masquerading, multiple local (PC) IP addresses are mapped to a single global IP
address. Many local (PCs) IP addresses are therefore hidden behind a single global
IP address. The advantage of this type of NAT is that users only need one global IP
address, but the entire local LAN can still access the Internet. This NAT technique
requires not only remapping IP addresses but also TCP and UDP ports.
Each PC on the LAN side has an IP address and a mask. When the router connects
to an ISP, the router appears to be a “host” with one IP address and mask. The IP
address that the router uses to communicate with the ISP is obtained dynamically
(with PPP/IPCP or DHCP) or is statically configured. When the PC connects to the
ISP, the IP address and port used by the PC are remapped to the IP address
assigned to the router. This remapping is done dynamically.
Client Configuration
The following procedures present client configuration from the CLI, for enabling NAT
via the WMI, see “NAT” on page 8-38.
Enable NAT
To enable NAT for a remote interface, use the commands:
-> remote setiptranslate on <remotename>
-> save
To enable NAT for an Ethernet interface, use the commands:
-> eth ip translate on <interface>
-> save
The save command makes the above changes persistent across reboots; these
changes turn NAT on when the specified interface is used.
Obtain an IP Address for NAT
The IP address (the IP address “known” by the remote ISP) used for this type of NAT
can be assigned in two ways.
The ISP dynamically assigns the IP address. Use the commands:
-> remote setsrcipaddr 0.0.0.0 0.0.0.0 <remotename>
-> save
The IP address is assigned locally. Use the commands:
-> remote setsrcipaddr ww.xx.yy.zz 255.255.255.255 <remotename>
-> save