SmartSwitch Router User Reference Manual 227Chapter 16: Network Address Translation Configuration GuideDynamic NAT with IP Overload (PAT) ConfigurationThe following example configures a dynamic address binding for inside addresses10.1.1.0/24 to outside address 192.50.20.0/24:The first step is to create the interfaces:Next, define the interfaces to be NAT “inside” or “outside”:Then, define the NAT dynamic rules by first creating the source ACL pool and thenconfiguring the dynamic bindings:Using Dynamic NAT with IP OverloadDynamic NAT with IP overload can be used when the local network (inside network) willbe initializing the connections using TCP or UDP protocols. It creates a binding at runtime when the packet comes from a local network defined in the NAT dynamic local ACLpool. The difference between the dynamic NAT and dynamic NAT with PAT is that PATuses port (layer 4) information to do the translation. Hence, each global IP has about 4000ports that can be translated. NAT on the SSR uses the standard BSD range of ports from1024-4999 which is fixed and cannot be configured by the user. The network administratordoes not have to worry about the way in which the bindings are created; he/she just setset.2.2(192.50.20.1/24)et.2.1(10.1.1.1/24)Global InternetIP network 10.1.1.0/24Routerinterface 10-net interface 192-net10.1.1.410.1.1.210.1.1.3Outbound: Translate source pool 10.1.1.0/24 to global pool 192.50.20.1-192.50.20.3interface create ip 10-net address-netmask 10.1.1.1/24 port et.2.1interface create ip 192-net address-netmask 192.50.20.1/24 port et.2.2nat set interface 10-net insidenat set interface 192-net outsideacl lcl permit ip 10.1.1.0/24nat create dynamic local-acl-pool lcl global-pool 192.50.20.1-192.50.20.3
