Panasonic 8000 - Manual (Page 133)

Nortel Secure Router 8000 Series
Troubleshooting - VAS__________
4 NAT troubleshooting
4.1.2 NAT modes
NAT has two modes. In one mode, NAT replaces only the IP address of the packet as shown
in Figure 4-1. In the other mode, NAT replaces both the IP address of the packet and the
number of the interface as shown in Figure 4-2, which is called Network Address Port
Translation (NAPT). NAPT can implement IP address sharing with high efficiency.
Therefore, NAPT is the most commonly used mode of NAT.
Figure 4-2 NAPT working mode
Internal
network
If
10.1.1.200:102^^' 211.100.7.34:80
External
network
162.105.178.65:1638^^ 211.100.7.34:80
10.1.1.200:102^^ 211.100.7.34:80
10.1.1.200 NAT Server
m
10.1.1.110:102^^“ 211.100.7.34:80
162.105.178.65:1638^^ 211.100.7.34:80
211.100.7.34
162.105.178.65:1640^^ 211.100.7.34:80
10.1.1.110:102^^ 211.100.7.34:80
10.1.1.110
162.105.178.65:1640^^ 211.100.7.34:80
m
NAT Server 211.100.7.34
162.105.178.65
162.105.178.66
162.105.178.67
162.105.178.68
Address pool
4.1.3 Special protocols supported by the address translation
The NAT platform module not only executes address translation, but also provides a NAT
application level gateway mechanism.
In this manner, it can support various application protocols in the flow without any changes in
the NAT platform. Therefore, NAT provides high scalability.
NAT supports address translation of the following protocols and application programs:
• Internet Control Message Protocol (ICMP)
• Domain Name System (DNS)
• Internet Locator Service (ILS)
• NetBIOS over TCP/IP (NBT)
Issue 01.01 (30 March 2009) Nortel Networks Inc. 4-3