Avocent Cyclades-PR2000 installation manual Nat Network Address Translation, 200.240.230.2

Cyclades-PR2000

CHAPTER 11 NAT (NETWORK ADDRESS TRANSLATION)

NAT exists to convert local IP addresses into Internet “global” IP addresses. Internet IP addresses are assigned by Internet providers. Due to the explosion of the internet, these numbers are scarce. Certain ranges of IP addresses are reserved for internal use only — they may not have a direct connection to the Internet (for reference, they are 10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.16.255.255, and 192.168.0.0 - 192.168.255.255). These are used as local IP addresses. Figure 11.1 shows an example of the utility of NAT:

200.240.230.2

PR2000 With Expanded NAT

Global Address Range	ftp
- Network: 200.240.230.224	Server
- Mask: 255.255.255.240	192.168.0.30
Host
Host
	PC

200.200.200.11

200.200.200.10

192.168.0.5

Router Ethernet Port

Primary IP Address: 192.168.0.1

Secondary IP Address: 200.200.200.1

FIGURE 11.1 NAT EXAMPLE

Networks 192.168.0.0 & 200.200.200.0

WWW

Server

192.168.0.31

In this example, the company has:

•14 global IP addresses available for NAT, 200.240.230.225 to 200.240.230.238,

•Two networks connected to the router via the Ethernet Interface, one of which will be translated,

•Two servers that are accessed via the same global IP address, assigned statically.

Chapter 11 - NAT 90