3Com Router 3031, Command Reference Manual

Page: 463 / 838

NAT Configuration Commands 463
This command is used to set the valid time of address translation connection, and
different time values are set for different types of protocols. The time value is in
second.
Example
Set the valid connection time of TCP to 240 seconds.
[3Com] nat aging-time tcp 240
nat outbound Syntax
nat outbound acl-number [ address-group group-number [ no-pat ] ]
undo nat outbound acl-number [ address-group group-number [ no-pat ] ]
View
Interface view
Parameter
■
address-group: Configures address translation by means of address pool. If the
address pool is not specified, use the IP address of the interface as the
translated address, i.e., the "easy ip" feature.
■
no-pat: Uses simple address translation, which means only to translate the
address of the packet but not use port information.
■
acl-number: ACL index in the range of 1 to 199 (the advanced ACL can be
used).
■
group-number: The number of a defined address pool.
Description
Using the nat outbound command, you can associate an ACL with an address
pool, indicating that the address specified in the acl-number can be translated by
using address pool group-number. Using the undo nat outbound command, you
can remove the corresponding address translation.
Translation of the source address of the packet that conforms to the ACL is
accomplished by configuring the association between the ACL and the address
pool. The system performs address translation by selecting one address in the
address pool or by directly using the IP address of the interface. Users can
configure different address translation associations at the same interface. The
corresponding undo form of the command can be used to delete the related
address translation association. Normally, this interface is connected to ISP, and
serves as the exit interface of the inside network.
The command without the address-group parameter implements the "easy-ip"
feature. When performing address translation, the IP address of the interface is
used as the translated address and the ACL can be used to control which
addresses can be translated.
Example
Enable the hosts of the 10.110.10.0/24 network segment to perform address
translation by selecting the addresses from 202.110.10.10 to 202.110.10.12 as
the translated address. Suppose that the interface Serial0/0/0 connects to ISP.
[3Com] acl number 1