Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 287)

Brocade Virtual ADX Server Load Balancing Guide 271
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Layer 7 content switching on HTTP response
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Layer 7 content switching on HTTP response
The Brocade Virtual ADX can perform content rewrite on the server responses. In other words, the
Brocade Virtual ADX can not only modify requests in the forward direction, but also the responses
in reverse direction. The HTTP response is divided into the "header" part and the "body" part. The
Brocade Virtual ADX can selectively rewrite the header, body, or both.
Response header rewrite
The response header rewrite feature is typically required in an SSL-Offload environment when the
real servers send redirect messages to the incoming clients.
Figure 31 shows such a scenario
when the Real-Server is not aware of the SSL-Offload but sends a redirect using HTTP. The Brocade
Virtual ADX does not change the response and sends it to the client. The Client, as a result, sends
another request using HTTP, and as a result, suddenly moves from a secure HTTPS to HTTP.
FIGURE 31 HTTP response header rewrite
A Brocade Virtual ADX can be programmed to modify such responses and replace "http://" with
"https://". This feature can be applied selectively based on the response code and the embedded
URL. For example, the Brocade Virtual ADX can be programmed to replace only response codes
301 and 302, and only for URLs matching "http://www.example6.com".
In general, this feature is used for modifying the redirect URLs in response codes 301 and 302.
However, it is not limited to modifying redirects and in theory can be configured to modify any other
part of the HTTP-header in any other response code.
Configuring HTTP header response rewrite
To enable response header-rewrite, follow these steps.
1. Create a CSW rule specifying the request rule or response codes to be acted upon.
2. Create a CSW rule specifying the string to be modified.
3. Create a CSW policy.
4. Bind the CSW policy to the virtual server port.