Read Radius Logs With PowerShell

Read Radius Logs With PowerShell

Recently, I have been troubleshooting radius. Radius hasn’t changed in decades. I say this lightingly too. The network policy server is a feature that helps with connecting things like unifi wifi and more. Each radius connection produces a reason code. Today we want to look through the radius logs and get as much useful information without screaming at the screen. Radius logs are a little daunting. This is why many people use an SQL server for the radius logs. However, if you are not one of those people who can do this, the traditional radius logging works wonders. So, we will read radius logs with PowerShell.

Radius Logging

Before we start, we need to know what we are dealing with. The standard location for readius logs is: C:\Windows\System32\LogFiles. You can change this location as you see fit. I personally changed my locations to a c:\logs\radius location. This helps me find it quicker and generally, I don’t have trouble guessing what is what. You can set the radius log location by doing the following:

  • Start Network Policy Server
  • Click account
  • Under Log File Properties click Change Log File Properties
  • A box will pop up called “Log File Properties” Click on the “Log File” tab.
  • This is where you can change your directory.
  • Change your Format to DTS Compliant. As this script works best with it.
  • I personally like smaller files when I am working with log searches. So I select the “When log file reaches this size:” I select 1 – 5 MB.
  • Click ok

Now your log files will live wherever you told them. You will need to change the script around a little if you are using a different location than me.

The Script and Breakdown

$NPSLogs = Get-content -Path "C:\Logs\Radius\IN2308.log" | Select-Object -Last 6
foreach ($NPSLog in $NPSLogs) {
        TimeStamp = ([xml]$NPSLog).event.Timestamp.'#text'
        ComputerName = ([xml]$NPSLog).event.'Computer-Name'.'#text'
        Sources = ([xml]$NPSLog).event.'Event-Source'.'#text'
        Username = ([xml]$NPSLog).event.'User-Name'.'#text'
        CalledStationId = ([xml]$NPSLog).event.'Called-Station-Id'.'#text'
        CallingStationId = ([xml]$NPSLog).event.'Calling-Station-Id'.'#text'
        NasPortType = ([xml]$NPSLog).event.'NAS-Port-Type'.'#text'
        NasIdentifier = ([xml]$NPSLog).event.'NAS-Identifier'.'#text'
        NasPort = ([xml]$NPSLog).event.'NAS-Port'.'#text'
        ClientIPAddress = ([xml]$NPSLog).event.'Client-IP-Address'.'#text'
        ClientVendor = ([xml]$NPSLog).event.'Client-Vendor'.'#text'
        ClientFriendlyName = ([xml]$NPSLog).event.'Client-Friendly-Name'.'#text'
        ProxyPolicyName = ([xml]$NPSLog).event.'Proxy-Policy-Name'.'#text'
        ProviderType = ([xml]$NPSLog).event.'Provider-Type'.'#text'
        SamAccountName = ([xml]$NPSLog).event.'SAM-Account-Name'.'#text'
        FQUsername = ([xml]$NPSLog).event.'Fully-Qualifed-User-Name'.'#text'
        AuthType = ([xml]$NPSLog).event.'Authentication-Type'.'#text'
        Class = ([xml]$NPSLog).event.Class.'#text'
        PacketType = ([xml]$NPSLog).event.'Packet-Type'.'#text'
        ReasonCode = ([xml]$NPSLog).event.'Reason-Code'.'#text'
        TunnelClientEndpt = ([xml]$NPSLog).event.'Tunnel-Client-Endpt'.'#text'

As you can tell, this script needs to be used on the server in question. However, You could wrap this script into a nice wrapper. That would allow you to execute on remote machines. The breakdown is very simple on this one as well. DTS is an XML format. Thus, you just need to use the [XML] before any of the lines. The XML is formatted with the event, it’s name, and the text. It’s a very simple setup. From there I select what I want and give it in a pscustom object. That’s it. Its a very simple setup. That’s why we should always read radius logs with Powershell.

Troubleshooting Radius – IP Changes

Troubleshooting Radius – IP Changes

Last October, I ran across a client with a broken radius. I want to go through the process I used to troubleshoot the issue. The goal of this to bring you a level of understanding of the troubleshooting processes. Not every process is the same for each It related item. Getting exposed to different steps from different people helps out.


Here is the scenario. The client called and stated that no one is able to connect to the wifi. I looked at the device and saw that they were connecting via Radius. Radius allows you to use your username and password for the domain to login into the wifi. It’s one of the more secure ways to setup wifi. I had no documentation to fall back on. Thus, I knew nothing about the radius setup. However, I did know about the wifi controller. It was an Unifi controller.

Troubleshooting Radius – Discovery

Since we know that the devices are connecting to the wifi that is controlled through the Unifi controller, the first logical step is to go to the Unifi controller. I logged into the Controller and went to the settings button at the bottom of the left-hand side of the menu. From there I clicked on the WiFi menu option. I want to look at the wifi profile of the Corporate wifi. The one they are trying to connect to. Next, I scrolled down to the Security area.

Under the Security area, You will see the Radius Profile. Take note of this name. We will call our bob. Once you have that name, Click the profile on the left-hand side of the screen.

At this point, we have discovered the Radius Profile Name. Next, we need to dig into the Profile itself. More information the better when troubleshooting radius. Once you click on the Profile, scroll down to the Radius Section. From here, I found the name of the profile from before and clicked it.

Here we could see the Authentication servers’ IP addresses and ports. Now we know which server Radius is living on. From here, I go to the devices and find the Device they are trying to connect to. Thankfully, the device was named correctly. If it isn’t, then that’s a whole other ball game. I noted the IP address and mac address of the device. The device was active with no connections.

Troubleshooting Radius on the Server

I used RDP to access the IP address with success. I am thankful because sometimes the radius can be setup using compliance of some sort. Next, I connected to the Network Policy Server. After that, I connected to the Radius clients. Looking over the Friendly names, and IP addresses from the Unifi controller and the Radius Server, the problem was clear.

DHCP change occurred on the access points. This meant the NPS radius client IPs were wrong. To correct this, all I have to do is update the NPS Radius client’s IP addresses. However, I don’t want this to happen again. So, here are the steps I took.

  1. Changed all the Access Points to Static instead of DHCP
  2. Change the NPS Radius Client IP addresses to match.

Once I did this, The client was able to reconnect to their wifi using their windows domain credentials.

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