Operation Manual – NAT, Netstream, Policy RoutingH3C S7500 Series Ethernet Switches Chapter 1 NAT Configuration1-10Note:z If the public IP address you configured for an internal server is the VLAN interfaceaddress on the NAT device, you cannot ping through the internal server (which actsas an ICMP server) from the NAT device with the public IP address. However, youcan avoid this problem by specifying a source IP address with the -a keyword in theping command.z Currently, secondary address translation on a NAT connection is not supported.z The internal hosts can only access the internal servers through the private IPaddresses instead of the public IP addresses of the servers (the public ones areused for external users to access the internal servers).z To use the NetMeeting software or enable an internal FTP server, you need toconfigure both the nat server and nat outbound commands. For details, refer tosection Configuring NAT.z For an FTP, TFTP, MSN voice, ILS, or H.323 internal server, besides using the natserver command to configure the translation from an external IP address to itsinternal IP address, you need to use the nat outbound command to configure thetranslation from its internal IP address (by referencing an ACL) to the external IPaddress (by referencing an address pool that contains only the IP address).1.3.5 Configuring Non-Standard Internal FTP ServerDifferent from standard internal FTP servers, non-standard internal FTP servers canuse extended private ports.z Standard internal FTP servers can use ports 0 through 12,287 as their public ports,and only port 21 as their private ports.z Non-standard internal FTP servers can use ports 0 through 12,287 as their publicports (same with standard internal FTP servers), and ports 0 through 65,535 astheir private ports.Caution:Among ports 0 through 65,535, any well-known ports other than port 21 cannot be usedas the private ports of non-standard internal FTP servers. (You can see thosewell-known ports on CLI by command help.)Follow these steps to configure a non-standard internal FTP server:
