Java applications and TMG access rules that require authentication

Hi there,

In this blog post, I’ll be talking about a TMG related issue. Actually it’s not an issue that stems from TMG itself but the way TMG server is configured (using authenticated rules on TMG server) triggers the problem.


This is already a known fact and we have a KB article that explains this issue (JVM applications cannot send authentication information when requested) and the workaround is to turn off authentication for the access rule that will allow the client’s connection to external networks: An ISA server or Forefront Threat Management Gateway server requests credentials when client computers in the same domain use Internet Explorer to access Web sites that contain Java programs


So if you see all or some parts of a web page is not displayed correctly and you see Proxy authentication required or similar messages on the client side and you suspect that Java is involved somehow you’ll have to implement the steps mentioned at the above article.

But sometimes it may not be that clear which was the case in my scenario. The customer reported that videos at an on demand video conference site weren’t successfully viewed and the application running inside IE was displaying an unrelated error. I suspected that we were hitting the problem mentioned above and then requested the customer to configure a temp access rule to allow all outbound access for “All users”, then the videos started to play J

Then we changed the rule target to the target web site only (you can do this via a URL set (for HTTP/HTTPS access) or via domain name set (for any protocols), you can find more information below: Processing domain name sets and URL sets

Since the customer was connecting to , we have added this domain to the rule target. But afterwards the video access was still failing. Then we decided to collect more information on what kind of http activity was taking place on the client side. I asked the customer to install Fiddler on the client to see this activity (you can download the tool at

You’ll find below a sample screen shot taken from Fiddler which was taken when accessing Microsoft’s web site:




As you can see from the above output, even if you see a certain address in IE ( in this example), the browser might need to connect to other related web sites to load some images, to get a script, etc etc. In the above example, browser also connects to or …


That was the case in my customer problem, even though the customer was connecting to, the browser was connecting to a few other web sites like * and * So we changed the relevant rule to cover these domain names as well and the problem was resolved:






Hope this helps




Comments (2)

  1. Anonymous says:

    Thanks for the feedback Richard. Definitely that's another solution, but somehow firewall client deployment isn't very common unfortunately :(. I think it still makes much sense to add this information here, thank you for the referral.

  2. Richard Hicks says:

    Hi Murat,

    Another way to resolve this issue for Windows clients is to install the Forefront TMG Firewall Client. The Firewall Client authenticates to the TMG firewall transparently. The application is unaware that it is communicating through an authenticating proxy. More information here:…/dd897009.aspx

    Richard Hicks