I am using WSA in transparent mode, ASA as WCCP redirector. I can not get some pages. (www.arspoetica.sk for instance) Browser (Mozila) open file save dialog with application/octet-stream application. But there is no such a stream from this page. When I configure (in my browser) the same WSA as explicit proxy, pages are displayed correctly. The same if I configure proxy bypass for this web sites.
I do packet capture from my PC and I saw I did not get 200OK response, but communication seems the same.
there are http URL. WCCP redirection on ASA is configured only for port TCP/80. HTTPS connections (TCP/443) goes directly to internet. When I did packet capture, I was looking particulary for this, because I know, that proxying https is an issue.
But I have problem only with transparent redirection of some (very few) http URL. And when I configure the same WSA proxy as explicit in client browser, it work without problem.
Thank you! for your response and update provided, if these sites/URL are http and failing through appliance, Please create a TAC case so we can help you isolate and resolve this issue ASAP.
PS. As for the https site in transparent mode, we MUST enabled - configure https proxy on the WSA appliance. otherwise you will get mixed results.
Here are the steps by step process for https proxy:
Steps to configure HTTPS Proxy and CSR Option on Web Security Appliance:
Steps to enable HTTPS proxy on (WSA) & Uploading Root/Intermediate certificate option.