In this guide, we will identify some possible causes that can lead to the expected C# type error, and after that, we will provide some possible fixes that you can try to get rid of this problem.
Approved: Fortect
I have an ISA authentication problem that has been bugging our support team for a day and a half; Any form of assistance at this stage would be greatly appreciated. Yes
We support a multi-domain account running on Server 2003 R2 with clustered ISA 2004 servers routing Internet traffic through this proxy server. Before the power outage in one of the domains (let’s call it “Domain A”) on Sunday evening, Internet requests from all places through the ISA were resolved very well. It’s also worth noting that the ISA Server cluster is not actually in Domain A, and none of the other sites in the domain appear to have lost performance anywhere, including the ISA Servers.
However, after frequent troubleshooting and bringing the affected nodes back online, domain A blog traffic is no longer processed through the proxy. Instead, the ISA log now contains the error “12209: ISA, the server requires authentication to complete the request. Access denied to Web proxy filter.” As a result, users will be denied access to ALL websitessites, including those they have visited before.
We don’t have problems with proxies with other types of domains, only domain A, which again might be the only one that went down during the outage. There is a forest-level mutual trust between domain A and the ISA domain. At this point, I broke that trust from the surface and rebuilt it to no avail.
Users attempting to access domain A sites appear to be blocked from connecting to the ISA server because they might be prompted for authentication. However, your username and password keep popping up in the login dialog, which leads me to believe that the problem is that ISA cannot properly validate the login information.The ISA Server error log shows many rejected connections to the IP address range of domain A, all caused by “user: anonymous”. Users from other domains will continue to authenticate and browse normally.
We’ve already tried a number of things, including restartingto Domain A’s server, DNS replication, reconfiguring the exact gateway router for Domain A to the actual settings before Sunday, and recreating the trust mentioned above on it… and so on, none of that helped.
For now, we have removed the proxy server from domain A group policy and users are working as normal. This is not a definitive fix, but any help in fixing this crazy ISA authentication problem would be a fantastic blessing.
Question
Hi, we are running TMG Forefront 2010 SP1 on a Windows 2008 r2 device configured as a web proxy. Clients sometimes start asking for a password randomly. After providing credentials, he refuses and after some time after logging out, he leaves on his own. What could be the problem?
Approved: Fortect
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