ThousandEyes Page Load test: NTLM communication example

[oatroshc]

Welcome to a series of articles about ThousandEyes!

ThousandEyes is a powerful SaaS platform that gives a digital picture of enterprise infrastructure, formed by test views, alerts, dashboards, and other components.

This article aims to dig deeper into the communication between a client and a server using the ThousandEyes Web Page Load test with NTLM authentication.

This article will cover:

• What NTLM is
• A quick recap on how ThousandEyes Web Page Load or HTTP tests work with NTLM
• Executing the test round while capturing the packets
• Analyzing the packet capture from the test round

 

What is NTLM?

In a Windows network, NT (New Technology) LAN Manager (NTLM) is a suite of Microsoft security protocols intended to provide authentication, integrity, and confidentiality to users. NTLM is the successor to the authentication protocol in Microsoft LAN Manager (LANMAN), an older Microsoft product. (Source: Wikipedia).

ThousandEyes Tests & NTLM:

Need a refresh on creating a Web-Page Load or HTTP test? Watch this 1-minute video:

Test-round execution, packet capture, and analysis

Now let's examine a successful test and how it appears in the tool. In the screenshot below, we see an HTTP response from the server showing "200 OK," confirming successful interaction.

We've added a red box outlining the area to view

To fully understand the interaction between the client and server, we captured the data from a test round. We filtered using cookie data to ensure we focused on the correct round and then followed the HTTP stream. This resulted in the following output:

A screenshot with numbered areas we will reference in the next sections of the article

Let's highlight the most interesting parts of the communication:

In line item [1] from the image, we see that Client 10.x.x.x sent the initial request in frame 13:

In line item [2] we see server 172.x.x.x responded with HTTP 401 Unauthorized with NTLM Challenge (frame 15):

In line item [3], frame 17, we see the client is now sending NTLM AUTH message, passing credentials, and the response should be in frame 350. 

Finally, in line item [4] frame 350 we see the server respond with HTTP 200 OK:

If you have any issues with ThousandEyes tests - open a chat with ThousandEyes Customer Support, we'll be happy to help! Here is an article on getting in touch with us in only a few seconds.

Reference to useful ThousandEyes resources:

• Main web page: thousandeyes.com
• ThousandEyes Test Settings for Page Load and Transaction Tests 
• Application page: app.thousandeyes.com