Connecting the world…


Citrix WebInterface 5.3 on IIS7

While configuring a Citrix NetScaler 9.2 in conjunction with WebInterface 5.3 I received the following error message when executing a published application.

An error occurred while trying to access the requested resource.

I thought to myself….no problemo, since I blogged about this problem before (source). This solution didn’t help. After changing the RequireLaunchReference value I still receive the error while opening an application. The only difference is that the event viewer message isn’t generated anymore.

After searching the internet I found another Citrix knowledge base article, called “Application Launch Failure in Web Interface 5.0 through 5.3”. This article provided me with the solution.

It looks like IIS 7 differs quite a lot from earlier versions. Citrix’s background on the problem:

It is currently suggested not to run .NET 1.1 or .NET 4.0 on a windows 2008 Web Interface server that is using Web interface 5.0 through 5.3. The .Net Framework 2.0 common language runtimes will be used in conjunction with the 3.0 and 3.5.

Don’t ask me what it is, because I don’t know. Switches, routers, firewall and other networking components don’t use Microsoft .NET…..

eSafe Proxy with NTLM v2.0

Today I am playing with eSafe 8 operating in eSafe Proxy with NTLM authentication mode. Configuring eSafe Proxy with NTLM authentication is very straightforward and not difficult. The authentication settings are configuring using the eSafe Appliance Manager web interface, like shown below.


I did some testing with multiple browsers and single sign-on with NTLM authentication is working perfectly. The system administrator was also testing, but he was complaining that he couldn’t authenticate. A pop-up box is received and when you enter the appropriate credentials, they aren’t accepted by eSafe. I found out that the customer is using Windows 7 and I was testing with Windows XP and Windows Server 2003.

Windows Vista, Windows 7 and Windows Server 2008 R2 and higher use NTLM v2.0-only by default. eSafe Proxy uses NTLM v1.0. The default setting within Windows can be changed to operate in a mode which is backwards compatible with eSafe Proxy. Take the following steps to change the NTLM settings:

  1. 1. Open the Group Policy Editor with gpedit.msc;
  2. 2. Go to Computer Configuration – Windows Settings – Security Settings – Local Policies – Security Options;
  3. 3. Go to the setting: Network security: LAN Manager authentication level
  4. 4. Change this setting to: Send LM & NTLM – use NTLMv2 session security if negotiated
  5. 5. Apply the policy with gpupdate /force


The picture shows the policy setting within Windows. This should solve the problem with single sign-on on Windows Vista, Windows 7 and Windows Server 2008 R2 and higher.

Where is the Internet Authentication Service?

Microsoft IAS server is often used as RADIUS server to authenticate VPN users or in conjunction with ISA reverse proxy to authenticate OWA users or PDA synchronization.

Today I had to install an ISA reverse proxy server with ISA 2006 Standard and Exchange 2007. I wanted to install Microsoft IAS as RADIUS server to authenticate the OWA users. Normally I install IAS on one, but preferably, on two domain controllers. I logged in on a domain controller through RDP. I noticed that the OS of the domain controller was Windows Server 2008.

Cool, finally working with a Windows Server 2008. After getting familiarized with the new view and layout, I started to search for a way to add the needed Windows component IAS. After searching for a while I found how to add Windows component. Looking at the complete list, I couldn’t find the Internet Authentication Service.

Oops, did Microsoft remove the IAS functionality from its server platform??? After googling for a second, I found that IAS has been replaced by Network Policy and Access Server service in Windows 2008.

Microsoft TechNet told me the following:

Network Policy Server (NPS) is the Microsoft implementation of a Remote Authentication Dial-in User Service (RADIUS) server and proxy in Windows Server 2008. NPS is the replacement for Internet Authentication Service (IAS) in Windows Server 2003.


As a RADIUS server, NPS performs centralized connection authentication, authorization, and accounting for many types of network access, including wireless and virtual private network (VPN) connections. As a RADIUS proxy, NPS forwards authentication and accounting messages to other RADIUS servers. NPS also acts as a health evaluation server for Network Access Protection (NAP). Source

After installing NPS, I started the configuration. You really have to get familiar with the way Windows Server 2008 works. There are a lot of different wizard and multiple configuration options to choose from. Everything looks a bit more fancy. NPS is not only a replacement for IAS, but has also many enhancements.

More information about installing and configuration Network Policy Server can be found in the article Understanding the new Windows Server 2008 Network Policy Server on Here you can read that NPS has a lot of functions related to Network Access Protocol (NAP). A very detailed example of using NPS to perform NAP can be found in Brian Posey’s series An Introduction to Network Access Protoction.