Operation Manual – NAT, Netstream, Policy RoutingH3C S7500 Series Ethernet Switches Chapter 1 NAT Configuration1-5which internal hosts the response packets should be forwarded to depending on thedestination addresses and port numbers carried in the packets.1.2.3 Easy IPThe Easy IP feature enables you to associate an ACL directly with the IP address of aVLAN interface that connects to the Internet by using the nat outbound command, sothat the NAT translates the source IP addresses of matching packets to this interfaceaddress. This feature is useful when only one public IP address (the interface address)is available or there are few internal hosts.1.2.4 Internal ServerNAT conceals an internal network from the Internet and acts as a shield for internalhosts. But in practical applications, it might be required to allow external hosts toaccess certain internal devices such as internal WWW servers or FTP servers. Byusing NAT, you can flexibly add internal servers with public IP addresses so that theservers can be accessed by external hosts. For example, you can:z Configure public IP address 202.169.10.10 for an internal WWW server.z Configure public IP address 202.110.10.11 for an internal FTP server.z Configure public IP address and port number 202.110.10.12:8080 for an internalWWW server.1.2.5 Special Protocols Supported by NATThe Comware NAT platform not only implements general NAT features, but alsoprovides complete NAT application-level gateway mechanism, enabling itself tosupport a variety of special application protocols without any changing on the platform.It has good scalability.The special protocols supported by NAT include Internet control message protocol(ICMP), domain name system (DNS), Internet locator service (ILS), H.323, FTP, andNetMeeting 3.01.1.3 Configuring NAT1.3.1 NAT Configuration Task ListComplete the following tasks to configure NAT:Task RemarksConfiguring a NAT Address Pool RequiredConfiguring NAT RequiredConfiguring Internal Server Required
