Are you using user level access control? This appears to be an authentication issue to me. HTTP requests from Yahoo! when passed to the webproxy via http redirector lose all user credentials and can be denied access cause of that. This also happens when you open Yahoo chat in yahoo messenger. It sends out http requests to get the chat room list and the list never arrives unless you disable the http redirector and convince yahoo not to pick up proxy settings from the browser (select the option "No Network Detection" in Yahoo connection settings).
Just disable the http redirector, tell yahoo to do "no network detection" and see if it works. Let me know how it went. I hope that'll help.
From: Dessesrt and Oil
could you please shed some light on this issue. actually though I ahve configured the Protocol Dfinitions correctly, but File transfer doenst work. VC, Webcam and chat works fine, but File Transfer doenst...
we are using one isa server for WebProxy (cache mode) and other as Firewall(firewall mode for winsock related services). I would appreciate your help if you could explain me this http redirector thing, as I m unable t understand it properly.
ISA services are arranged in a layered architecture.
NAT driver on the top. (processes only defined protocols from NAT clients. All these requests pass through the firewall service too.)
Firewall service. (processes all ip traffic, defined or not defined in protocol definitions. Web protocol requests are redirected to the webproxy service so they can take advantage of the webcache feature provided by webproxy. This redirection is provided by a built-in applicaiton filter known as the http redirector.)
Webproxy. (processes web requests from web proxy clients as well as requests redirected from the firwall service).
HTTP redirector issues pop up when you're using user level authentication with http redirector enabled. If an application not configured to use webproxy generates web protocol requests, they'll be redirected to webproxy service by the firwall service. In this process, the user credentials are ripped off by the http redirector. The webproxy service doesn't see any user credentials with the received request so it simply denies the request. (This is why Yahoo chat and file transfers 'cause problems with user level authentication.)
I suppose the first thing you should do is confirm whether this IS an authentication issue or NOT. Disable user level authentication for some time and go for allowing any request. If everything seems to start working then, you know you have authentication issues. Then you can get on to dealing with them.
I'd appreciate it if you could explain your scenario a bit clearly. How are your ISA boxes chained together and how are your clients configured? I hope I can be of any help.