Nat Configuration Task List - H3C S9500 Series Operation Manual

Operation Manual – L3+NAT
H3C S9500 Series Routing Switches
Easy IP applies to scenarios where there is only one public network interface address
or there are only a few internal host addresses.
V. Support for special protocols
Apart from the basic address translation function, NAT also provides a perfect
application layer gateway (ALG) mechanism that supports translation for some special
application protocols without requiring the NAT platform to be modified, featuring high
scalability. The IP addresses and/or port numbers contained in such protocol
messages need address translation. The special protocols supported by the S9500
series include: Internet control message protocol (ICMP), domain name system (DNS),
Internet locator service (ILS), and NetBIOS over TCP/IP (NBT).
VI. NAT multiple-instance
This feature allows users from different MPLS VPNs to access external networks
through the same outbound interface. It also allows them to have the same internal
network address. The process works as follows:
When an MPLS VPN user communicates with an external network, NAT replaces its
internal IP address and port number with the NAT gateway's external IP address and
port number. It also records the relevant MPLS VPN information, such as the protocol
type and router distinguisher (RD for short). When the response packet arrives, the
NAT gateway then restores the external IP address and port number to the internal IP
address and port number. Additionally, the NAT gateway can identify the users who
access the external network. Besides NAT, NAPT also supports multiple-instance.
The multiple-instance feature can also apply to internal servers so that external users
can access an internal host of an MPLS VPN. For example, in MPLS VPN1, the host
that provides WWW service has an internal address 10.110.1.1. The host can use
202.110.10.20 as an external IP address so that the Internet users can access the
WWW service in MPLS VPN1 through this external address.

1.2 NAT Configuration Task List

Follow the following steps to configure NAT:
Enter system view
Define an address pool
Configure address
translation
To do...
system-view
nat address-group
group-number start-address
end-address
Refer to
Translation.
Use the command...
Configuring Address
1-6
Chapter 1 NAT Configuration
Remarks
—
Optional
Not necessary when the
switch has been
configured with Easy IP.
Required