Web Agent Guides › Web Agent Configuration Guide › Use Web Agents with Proxy Servers › Configure Agents that Sit behind Proxy Servers

Configure Agents that Sit behind Proxy Servers

If a Web Agent will be installed behind a proxy server, you can configure the Web Agent to work with proxy servers using the following parameters:

• ProxyTrust

  Instructs the Web Agent for the destination server to trust the authorizations made by the proxy server. This is more efficient because the Web Agent for the destination server does not need to reauthorize users.

  Default: No

• ExpireForProxy

  Prevents a forward proxy server from caching content (pages and potentially headers or cookies). When this parameter is set to yes (enabled), the Web Agent inserts an Expires or Cache-control header into the HTTP response. If content is not cached, subsequent requests continue to be forwarded.

  When the ExpireForProxy parameter is set to yes, the Web Agent inserts the strings specified in the appropriate ProxyHeaderssuffix parameter into the HTTP response based upon what type of request was performed.

  The Web Agent adds strings into the HTTP responses as follows:

  • For HTTP/1.1 requests—if the resource is auto-authorized, then the Web Agent inserts the value of all ProxyHeadersAutoAuth parameters into the HTTP response. If the resource is protected, then the Web Agent inserts the value of all ProxyHeadersProtected parameters into the HTTP response. If the resource is not protected, then the Web Agent inserts the value of all ProxyHeadersUnprotected parameters into the HTTP response.
  • For HTTP/1.0 requests—if the resource is auto-authorized, then the Web Agent inserts the value of all ProxyHeadersAutoAuth10 parameters into the HTTP response. If the resource is protected, then the Web Agent inserts the value of all ProxyHeadersProtected10 parameters into the HTTP Response. If the resource is not protected, then the Web Agent inserts the value of all ProxyHeadersUnprotected10 parameters into the HTTP response.

  Default: No

  Note: This parameter applies to proxy servers only.

To tell the proxy not to cache the pages, the Web Agent adds an Expires header for the page. This header is set to a date in the past, which prevents the page from being cached by a proxy, as dictated by the HTTP 1.0 specification. On 302 redirects, a cache-control: no-cache header is set instead. Although this prevents caching of content, this has the negative consequence of affecting the browsing experience for an Internet Explorer (IE) browser, as described by Microsoft Support.

With the use of cache-control: no-cache for 302 redirects, the ActiveX component that manages in-place document viewing in IE relies on the browser's cache to locate the file. Because this header instructs the browser not to cache the file, the ActiveX component cannot locate the file and fails to display the request properly. Further, when you set the Web Agent's ExpireForProxy setting to yes, the back-end server tells the proxy not to cache the resource.

To configure Agents that sit behind proxy servers

1. Set the ProxyTust parameter to yes.
2. Set the ExpireForProxy parameter to yes.
3. (Optional) Customize the cache-control and ExpireForProxy (HTTP) headers.

   The Agents behind the proxy servers are configured.