General Information on Network Address Translation

With the explosive growth of the Internet, IP address depletion becomes a problem. Network address translation (NAT) provides a solution to the IP address depletion problem by allowing addresses inside your secured IP network to be reused by any other IP network.

Network address translation translates secured IP addresses to temporary external registered addresses from the address pool in order to communicate with the outside world. IBM provides network address translation for any TCP or UDP application, which does not require changes in the data transferred. In addition, ftp is supported by providing translation of the IP address in the port command.

Further Information

Translating Network Addresses

Type of NAT

Choose which type of Address you would like this NAT entry to be:

Registered IP Address

In the Registered IP Address entry field, enter a dotted-decimal IP address that identifies a range of Registered IP addresses added to the Registered address pool.

Registered IP Mask

In the Registered IP Address Mask field, enter a mask, like a subnet mask that specifies the bits in the Registered IP address used to add a range of IP addresses to the registered address pool.

Bits in these masks that are set to 0 indicate that bit positions that have 0 or 1 are reserved registered IP addresses. Hence, specifying a mask of 255.255.255.255 indicates only one registered address is added to the registered address pool, whereas a mask of 255.255.0.0 causes Class B IP addresses to be added to the registered address pool.

Secured IP Address

In the Secured IP Address field, enter a dotted-decimal IP address that identifies a range of Secured IP addresses that requires Network address translation.

Secured IP Mask

In the Secured IP Address Mask field, enter a mask, like a subnet mask that specifies the bits in the Secured IP address used to identify a range of IP addresses.

Bits in these masks that are set to 0 indicate that bit positions that have 0 or 1 are included in the range of IP addresses. So, specifying 255.255.255.255 in the mask indicates only one Secured IP address is included in this translation entry, whereas a mask of 255.255.255.0 indicates class C IP addresses require address translation.

Timeout

The Timeout Value specifies the number of minutes if an address translation stays idle, after which NAT should free the registered IP address. This Timeout Value only applies to the address translation which uses a registered IP address within the range of IP addresses specified by this entry.

OK

Press the "OK" button to save changes and close the window.

Cancel

Press the "Cancel" button to close the window without saving any changes.