Cabletron Systems 9032578-05 manual Dynamic NAT with IP Overload PAT Configuration

Chapter 16: Network Address Translation Configuration Guide

Dynamic NAT with IP Overload (PAT) 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 192.50.20.1-192.50.20.3

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

Global Internet

interface 192-net (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

Next, define the interfaces to be NAT “inside” or “outside”:

nat set interface 10-net inside nat set interface 192-net outside

Then, define the NAT dynamic rules by first creating the source ACL pool and then configuring the dynamic bindings:

acl lcl permit ip 10.1.1.0/24

nat create dynamic local-acl-pool lcl global-pool 192.50.20.1-192.50.20.3

Using Dynamic NAT with IP Overload

Dynamic NAT with IP overload can be used when the local network (inside network) will be initializing the connections using TCP or UDP protocols. It creates a binding at run time when the packet comes from a local network defined in the NAT dynamic local ACL pool. The difference between the dynamic NAT and dynamic NAT with PAT is that PAT uses port (layer 4) information to do the translation. Hence, each global IP has about 4000 ports that can be translated. NAT on the SSR uses the standard BSD range of ports from 1024-4999 which is fixed and cannot be configured by the user. The network administrator does not have to worry about the way in which the bindings are created; he/she just sets

SmartSwitch Router User Reference Manual 227