Microsoft IIS SMTP Server through NXLog

When you configure your Microsoft IIS SMTP Server to send log data to USM Appliance, you can use the Microsoft IIS NXLog plugin to translate raw log data into normalized events for analysis. The table below provides some basic information for the plugin.

Plugin Information
Device Details
Vendor Microsoft
Device Type SMTP server
Connection Type Syslog
Data Source Name iis-nxlog
Data Source ID 1502

Integrating Microsoft IIS SMTP Server and NXLog

Before you configure Microsoft IIS SMTP Server to send logs to USM Appliance through NXLog, you must first enable logging in ASCII text format on the SMTP virtual server.

Configure SMTP Logging

To configure SMTP logging in IIS Manager

  1. Open IIS Manager.
  2. Right click on the SMTP Virtual Server and select Properties.
  3. Check Enable logging and select W3C Extended Log File Format.
  4. Click Properties next to the log format.

    1. On the General tab, select Daily and keep the default log file directory

      Enable SMTP logging General

      Important: The AlienVault plugin looks for the C:\\Windows\\System32\\LogFiles\\SmtpSvc1\\ex* files by default. Therefore, if you change the location for the log files, you must update the nxlog.conf file (see below) accordingly.

    2. On the Advanced tab, select all Extended Properties except Protocol Substatus.

      Enable SMTP logging Advanced

  5. Click OK.

Configure NXLog on Windows

To send log data through NXLog to USM Appliance

  1. If not done already, download nxlog.conf, and then place it in the conf directory of your NXLog installation. Depending on which version you use, the directory can be C:\Program Files (x86)\nxlog\conf\ for the 32-bit version or C:\Program Files\nxlog\conf\ for the 64-bit version.

    Note: This step overwrites the default nxlog.conf file. You may want to back up the original copy before placing the one provided by AT&T Cybersecurity.

  2. Open the nxlog.conf file in a text editor.
  3. Update the root path of your NXLog installation.

    1. Locate the following lines:

      #define ROOT C:\Program Files\nxlog

      #define ROOT C:\Program Files (x86)\nxlog

    2. Uncomment the path that matches the NXLog installation on your Windows machine.
  4. Enter the USM Appliance Sensor IP address.

    1. Locate the following line:

      define OUTPUT_DESTINATION_ADDRESS <USM-Appliance-Sensor-IP>

    2. Replace <USM-Appliance-Sensor-IP> with the IP address of the USM Appliance All-in-One or USM Appliance Sensor that will receive the Windows events.
  5. Uncomment the section between IIS-SMTP-NXLOG and /IIS-SMTP-NXLOG.

    Important: Only remove the first # symbol in each line when uncommenting the sections. The remaining # symbol indicates that the line is either a comment or optional.

  6. In addition, uncomment the following lines, above the DHCP-NXLOG section:

    #<Extension json>

    # Module xm_json


  7. Save the file.
  8. Start or restart the NXLog service.

Plugin Enablement

For plugin enablement information, see Enable Plugins.

If enabling the plugin on assets, you will find it listed as Microsoft : IIS Internet Information Services : NXLog.

Enabling the iis-nxlog plugin from asset

Additional Resources and Troubleshooting

For troubleshooting, refer to the vendor documentation:

NXLog User Guide