Cabletron Systems 9032578-05 manual Dynamic Configuration, Using Static NAT

Chapter 16: Network Address Translation Configuration Guide

Using Static NAT

Static NAT can be used when the local and global IP addresses are to be bound in a fixed manner. These bindings never get removed nor time out until the static NAT command itself is negated. Static binding is recommended when you have a need for a permanent type of binding.

The other use of static NAT is when the out to in traffic is the first to initialize a connection, i.e., the first packet is coming from outside to inside. This could be the case when you have a server in the local network and clients located remotely. Dynamic NAT would not work for this case as bindings are always created when an in to out Internet connection occurs. A typical example is a web server inside the local network, which could be configured as follows:

nat create static protocol tcp local-ip 10.1.1.2 global-ip 192.50.20.2 local-port 80 global-port 80

This server, 10.1.1.2, is advertised as 192.50.20.2 to the external network.

Dynamic Configuration

The following example configures a dynamic address binding for inside addresses 10.1.1.0/24 to outside address 192.50.20.0/24:

Outbound: Translate source pool 10.1.1.0/24 to global pool 192.50.20.0/24

			10.1.1.4
					Router
IP network 10.1.1.0/24								Global Internet
					et.2.1	et.2.2
	10.1.1.3	10.1.1.2		interface 10-net			interface 192-net
				(10.1.1.1/24)		(192.50.20.1/24)

The first step is to create the interfaces:

interface create ip 10-net address-netmask 10.1.1.1/24 port et.2.1 interface create ip 192-net address-netmask 192.50.20.1/24 port et.2.2

SmartSwitch Router User Reference Manual 225