Enterasys Networks X-PeditionTM Dynamic Pool Configuration, Configuring Dynamic Pool Translation

Configuring NAT Examples

Dynamic Pool Configuration

The following example illustrates dynamic pool translation on the XSR, as shown in Figure 5-12.

Figure 5-12 Dynamic Pool Translation

Inside					Outside
	Request
	SA: 10.1.1.1						172.21.2.1
	DA: 172.21.2.1
10.1.1.1	NAT Table						Reply
	10.1.1.1	200.2.2.1					packet 1
			After Translation
Reply after							DA: 200.2.2.1
	After packet 1			DA: 172.20.2.1			SA: 172.21.2.1
reverse lookup				SA: 200.2.2.1		Internet
SA: 172.21.2.1	Internal
DA: 10.1.1.1	interface
		XSR
				External
Request				interface
packet 2							172.21.2.2
SA: 10.1.1.2
		NAT Table					Reply
DA: 172.21.2.2
10.1.1.2	Reply after	10.1.1.1		200.2.2.1	After Translation		packet 2
							DA: 200.2.2.2
	reverse lookup	10.1.1.2		200.2.2.2
	SA: 172.21.2.1	After packet 2			DA: 172.21.2.2		SA: 172.21.2.2
	DA: 10.1.1.1				SA: 200.2.2.2

Configuring Dynamic Pool Translation

Dynamic pool translation, as shown in Figure 5-12, is performed through the following process:

1.The user at address 10.1.1.1 opens a connection to address 172.21.2.1

2.The first packet that the XSR receives from address 10.1.1.1 forces a NAT Pool table check. If no dynamic pool entry exists, and address 10.1.1.1 must be translated, then the XSR adds a pool entry. The router replaces the inside local address 10.1.1.1 with the inside global address 200.2.2.1, and forwards the packet. Any other connections originating from address 10.1.1.1 will use address 200.2.2.1 as the global address.

3.Host address 172.21.2.1 receives the packet, and responds to address 10.1.1.1 by using the inside global address 200.2.2.1.

4.When the XSR receives the packet, it searches its NAT Pool table, using address 200.2.2.1, translates the address to inside local address 10.1.1.1, and forwards it to address 10.1.1.1.

5.The same process applies to the connection originating from address 10.1.1.2, but a different global IP address is used.

Now enter the commands below to set dynamic pool translation. Note some steps are optional.

1.Create local IP pool NATpool with excluded IP addresses (optional) and quit Local Pool mode:

XSR(config)#ip local pool NATpool 200.2.2.0 255.255.255.0 XSR(ip-local-pool)#exclude 200.2.2.1 8 XSR(ip-local-pool)#exclude 200.2.2.21 233 XSR(ip-local-pool)#exit

2.Register the global NAT pool:

XSR(config)#ip nat pool NATpool

XSR User’s Guide 5-39