Table of Contents
Advertisement
S9700 Core Routing Switch
Configuration Guide - SPU
The mapping indicates that one overlapping address pool maps one temporary address pool. The
translation rules are as follows:
Temporary address = Start IP address in the temporary address pool + (Overlapping IP address
- Start IP address in the overlapping address pool)
Overlapping address = Start IP address in the overlapping address pool + (Temporary IP address
- Start IP address in the temporary address pool)
When PC2 on the private network accesses PC3 on the public network using the domain name,
packets are processed as follows:
1.
2.
3.
4.
Source Address Associated with the VPN Before NAT Is Performed
The NAT-enabled SPU allows users on private networks to access the public network and allows
users in different VPNs to access the public network through the same egress. In addition, users
in the VPNs with the same IP address can access the public network.
NAT Server Associated with VPNs
The NAT-enabled SPU supports association between VPNs and NAT server, and allows users
on the public network to access hosts in the VPNs. This function is applicable when IP addresses
of multiple VPNs overlap.
3.3 Configuring NAT
To implement communication between the private network and the public network through
NAT, use Easy IP for a single user and an address pool for multiple users.
3.3.1 Establishing the Configuration Task
Before configuring NAT, familiarize yourself with the applicable environment, complete the
pre-configuration tasks, and obtain the required data.
Issue 01 (2012-03-15)
PC2 sends a DNS request for resolving the domain name www.web.com of the web server.
After the DNS server resolves the DNS request, the SPU receives the response packet from
the DNS server. The SPU resolves the address 10.0.0.1 in the payload of the response packet
and detects that the address is an overlapping address (it is in the overlapping address pool).
The SPU translates the address 10.0.0.1 into the temporary address 3.0.0.1, and translates
the destination address of the response packet using basic NAT. Then the SPU sends the
packet to PC2.
PC2 sends an access request packet with the temporary address 3.0.0.1 corresponding to
www.web.com to access the public network. When the packet reaches the SPU, the SPU
translates the source address of the packet using basic NAT and then translates the
destination address (temporary address) to the overlapping address 10.0.0.1.
The SPU sends the packet to the WAN-side outbound interface. The packet is then
forwarded to PC3 hop by hop.
When the packet sent from PC3 to PC2 reaches the SPU, the SPU checks the source address
10.0.0.1, which is the overlapping address (it is in the overlapping address pool). The
SPU translates the source address to the temporary address 3.0.0.1, and translates the
destination address using basic NAT. Then the SPU sends it to PC2.
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
3 NAT Configuration
89
Advertisement
Table of Contents
