Chapter 19: Lsnat Configuration; Configuring Load Sharing Network Address Translation (Lsnat); About Lsnat; Lsnat Configuration Considerations - Enterasys Matrix DFE-Gold Series Configuration Manual

This chapter describes the Load Sharing Network Address Translation (LSNAT) configuration set
of commands and how to use them.

Configuring Load Sharing Network Address Translation (LSNAT)

LSNAT is an advanced routing feature that must be enabled with a license key. If you have purchased an
advanced license key, and have enabled routing on the device, you must activate your license as described in
Activating Licensed Features on page
purchase an advanced routing license, contact Enterasys Networks Sales.

About LSNAT

As defined in RFC 2391, LSNAT supports network reliability and availability by enabling high
traffic servers to load balance. It allows an IP address and port number to become a Virtual IP
address and port number (VIP), mapped to many devices. When the VIP is seen as a destination
address and destination port number by the LSNAT device, the device traps the packet and then
translates the VIP to a real IP address and port combination. It does this by using a selected
algorithm for choosing from the group of server addresses, and replaces the VIP with the selected
IP address and port number. For outgoing transmissions, the translation is made from the real IP
address and port combination to VIP.

LSNAT Configuration Considerations

The following considerations must be taken into account when configuring LSNAT on Enterasys
Matrix Series devices:
• On chassis‐based systems, only one router per chassis will be allowed to run LSNAT at a given
time.
• ALL modules in the chassis must have upgraded memory to 256 MB, and must have an
advanced license activated.
• A server farm cannot be shared by different virtual servers.
Router: Unless otherwise noted, the commands covered in this chapter can be executed only
when the device is in router mode. For details on how to enable router configuration modes, refer to
Enabling Router Configuration Modes on page
Note: An Enterasys Feature Guide document that contains a complete discussion on LSNAT
configuration exists at the following Enterasys web site:
manuals/
LSNAT Configuration
2-103.
Important Notice
2-58. in order to enable the LSNAT command set. If you wish to
Enterasys Matrix DFE-Gold Series Configuration Guide 19-1
19
http://www.enterasys.com/support/