3Com 10014299 Performance of Network Address Translation NAT, Configure address pool, Pool-name

Configure Network Address Translation (NAT) 351

■The debugging of the network becomes even more difficult. For instance, when one host machine of the internal network attempts to attack other networks, it is very difficult to pinpoint which computer is attacking computer, since the IP address of the host machine is shielded.

Performance of Network Address Translation (NAT)

When the speed of the broadband of the link is below 1Mbps, the address translation has little impact on the performance of the network. In this case, the bottleneck of the network transmission is on the transmission line. When the speed is above 1Mbps, the address translation will have some impact on the performance of the routers.

Configure NAT NAT configuration includes:

■Configure the address pool

■Configure the correlation between the access control list and address pool

■Configure the correlation between the access control list and the interface (EASY IP)

■Configure the internal server

■Configure the valid time of address translation

1Configure the address pool

The address pool is a pool of the consecutive IP addresses. When the internal data packet arrives at the external network through address translation, it will select one address from the address pool as the translated source address.

Please process the following configurations in the system view.

Table 383 Configure address pool

Operation	Command
Define one address pool	nat address-group start-addr
	end-addr pool-name
Delete one address pool	undo nat address-group
	pool-name

All the addresses in the address pool should be consecutive. For the most, 64 addresses can be defined in each address pool.

An address pool can not be deleted, if it is correlated to one access control list and address translation has started.

2Configure the correlation between the access control list and address pool

Multiple-to-multiple address translation can be implemented, after the access control list and the address pool are correlated. The access control list is generated by rule command. It defines some rules, according to the format of the header of the IP data packet message and the header of data packet of the lower layer protocol it bears, which denotes the enable or disable of the data packets with certain features. For the data packet configured with NAT, it goes though address analysis before the message is forwarded. For the data packet no configured with NAT, it goes ahead with the normal forwarding process.

s according to this correlation relationship the addresses are translated. When the data packets of the internal network are to be transmitted to the external network: firstly, it is determined if the data packets are allowed according to the