Adding the X-Forwarded-For header via the KEMP LoadMaster

The X-Forwarded-For (XFF) HTTP header field is a standard method for identifying the originating IP address of a client connecting to a server through the KEMP LoadMaster or any proxy.

The KEMP LoadMaster allows us to give the client's IP to the destination Real Server by inserting an additional HTTP header (called X-Forwarded-For) when L7 is used with non-transparency.

This option of inserting the HTTP header (called X-Forwarded-For) allows the client source IP address to be logged by the Real Server's IIS logs.

Adding the X-Forwarded-For via the LoadMaster can be done either as a global setting or as a per-Virtual Service setting. Refer to the relevant section below for steps on how to add the header.


Global Setting

In the main menu of the LoadMaster Web User Interface (WUI), select System Configuration > Miscellaneous Options >  L7 Configuration and select X-Forwarded-For in the Additional L7 Header drop-down list. 


Per-Virtual Service Setting 

To add the X-Forwarded-For header via the LoadMaster per-Virtual Service, follow the steps below:

  1. In the main menu of the LoadMaster WUI, select Virtual Services > View/Modify Services.
  2. Click Modify on the relevant Virtual Service.
  3. Expand the Advanced Properties section.
  4. Add HTTP Headers > Select either"X-Forwarded-For (No Via) or X-Forwarded-For (Via)." option 


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This does not appear to be accurate for version The Per-Virtual Service Settings are different.

Andres Garcia de Alba

It is possible that your virtual service is on 443 and is not configured for SSL Acceleration?

If SSL Acceleration is not enabled, then the LM cannot decrypt the connection for the purpose of injecting the XFF header.

Thank you.