IIS X-Forward-For ISAPI Filter
A recent customer issue came up where they were load balancing servers but we unable to get the true client address logged in their IIS logs. They had their servers fronted by a BIG-IP and wh...
Published Sep 23, 2005
Version 1.0
This filter does not do anything with the headers. It looks for a header (X-Forwarded-For by default, but overridable by a ini file). If that header is found, it replaces the contents of the IIS C-IP value with the contents of that header.
It does not add or remove headers so any HTTP header that is passed into it, will be passed on to the web application. There is no rewriting needed as this is just a filter. It just sniffs whats coming in and passes it through to the backend.
So, if a X-Forwarded-For header is passed it to the filter, it will be passed out as well. Are you seeing different behvavior? The source is available for download as well if you want to look for yourself at what the filter does.
-Joe