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3529 - Troubleshoot DHCP option filter in NIOS


A custom client has been deployed on the network that requires vendor specific option (option 42), details listed in the table below. The network team has already setup the custom DHCP option space named IBDHCP, configured it with the 2 custom codes (10 and 15), and set up a filter to look for the special client IBEDU.sauron-2022_10_21.

Option Space

Option Number

Option Name

Option Type

Option Value





Santa Clara





However, client is not receiving these options. Please troubleshoot. You may use these 3 commands to help you on the testing-linux: 

  • To enable DHCP on the testing-linux, type: sudo set-network-dhcp

  • To disable DHCP on the testing-linux, type: sudo set-network-disable

  • To clear DHCP lease on the testing-linux, type: sudo clear-dhcp-leases

  • To show the current eth2 DHCP lease information, type: sudo show-dhcp-lease

When successfully configured, the command sudo show-dhcp-lease will print out the encapsulated options as follows:

 --- Encapsulated DHCP Options (vendor_encapsulated_options)
Decoding part 1: a:b:53:61:6e:74:61:20:43:6c:61:72:61
 Option ID: 10
 Option length: 11
 Option value: "Santa Clara"
Decoding part 2: f:4:c6:a:9:d
 Option ID: 15
 Option length: 4
 Option value: ""

Estimate Completion Time

  • 25 to 30 minutes






Grid Manager UI




  • Administrative access to the Grid

Course References 

  • 3012: DHCP Troubleshooting Methodology

  • 3018: Configuring NIOS DHCP Option Spaces and Filters

Lab Initiation

Access jump-desktop

Once the lab is deployed, you can access the virtual machines required to complete this lab activity. To initiate the lab, click on the jump-desktop tile and login to the Linux UI:

Username: training

Password: infoblox

Initiate lab

To initiate the lab, double-click the Launch Lab icon on the Desktop.

Launch Lab

Launch Lab

Choose the lab number from the list and click OK.

After clicking OK, you will see a pop-up message with a brief description of the lab task. If the description looks correct, click Yes to continue lab initiation.

Lab initiation will take a couple of minutes to finish.

Once complete, you will see another pop-up message with the login credentials and the URL for the Grid Manager’s User Interface. Note that the credentials may differ from those from prior labs.

Screenshot 2024-05-06 at 3.16.57 PM.png


To complete this lab, you need to perform the following tasks.

  1. Investigate and troubleshoot Custom Vendor Option delivery

Task 1: Troubleshoot DHCP Custom Vendor Option delivery

Check Option Space and Option Filter configuration to investigate why the Client is not getting the correct value in DHCP Option 43


Task 1 Solution: Troubleshoot DHCP Custom Vendor Option delivery

sudo set-network-dhcp command will get the client a DHCP lease, but not the correct vendor-specific options:

$ sudo show-dhcp-lease

--- Raw DHCP Lease Information

lease {
  interface "ens160";
  option subnet-mask;
  option dhcp-lease-time 43200;
  option dhcp-message-type 5;
  option dhcp-server-identifier;
  renew 1 2023/06/19 15:08:50;
  rebind 1 2023/06/19 20:53:49;
  expire 1 2023/06/19 22:23:49;

At this point, you should review the member configuration before running a traffic capture. The member configuration file (Data Management  DHCP  Member, select member, click Toolbar  View DHCP Configuration  IPv4) will show that the option space is properly setup, but in the network, these option values are not specified (blank).

If you navigate to the network, you will see that the fields under Custom DHCP Options are empty:

To properly finish the configuration, edit the network, click IPv4 DHCP options, under Custom DHCP Options, enter the correct values as shown below:


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