2588 - Consolidated NIOS DDI DHCP Administration Lab

Services submenu under Grid → Grid Manager can give us the statuses of all services in the Grid.

1. Login to NIOS GM web interface.

2. Navigate to Grid → Grid Manager → Services.

3. Select the DHCP tile and verify DHCP service status for the members.

4. Note the IP address 10.100.0.105 is configured to the member ibns1.techblue.net, and 10.200.0.105 is configured to the member ibns2.techblue.net.

5. If the service is not started, place checkmarks in the boxes for both ibns1.techblue.net and ibns2.techblue.net.

6. Click the Start button above the table and click Yes in the confirmation window to start DHCP service on selected members.

7. Use the Refresh button to update the status display

Subtask 2.1 Solution: Configuring the default domain name option

Assigning Domain Name techblue.net as the default value for all DHCP members in the Grid.

1. Navigate to Data Management → DHCP and select Grid DHCP Properties from the Toolbar on the right.

2. Select the section or tab from the left IPv4 DHCP Options.

3. In the Domain Name field, enter techblue.net.

Subtask 2.2 Solution: Configuring default DNS servers

Assigning 10.100.0.105 and 10.200.0.105 as default DNS servers for all DHCP members in the Grid

1. Navigate to Data Management → DHCP and select Grid DHCP Properties from the Toolbar on the right

2. Select the section for IPv4 DHCP Options.

3. Click the Add button under the DNS Servers section

4. Click directly in the field below IP Address and enter the IP address of the first DNS server: 10.100.0.105

5. After entering the first DNS server, click the Add button again and enter the IP address of the second DNS server: 10.200.0.105

Subtask 2.3 Solution: Configuring default lease time

Configuring default lease time for all DHCP members in the Grid

1. Navigate to Data Management → DHCP and select Grid DHCP Properties from the Toolbar on the right

2. Select the General section

3. Change value for Lease Time to 5 

4. Change the drop-down list to Minutes

Subtask 2.4 Solution: Configuring DHCP servers to be authoritative

1. Navigate to Data Management → DHCP and select Grid DHCP Properties from the Toolbar on the right

2. Select the General section

3. Check the option for DHCP server is authoritative

Subtask 2.5 Solution: Restarting DHCPv4 services

1. Restart the DHCP Service by clicking the Restart button in the notification banner at the top of Grid Manager

2. At the Restart Grid Services window, click Restart

Subtask 3.1 Solution: Creating a DHCPv4 network

1. Navigate to Data Management → DHCP → Networks → Networks

2. Click the Add dropdown menu and select IPv4 Network

3. Select the radio button for Add Network

4. Click Next

5. At Step 2 of 6 of the Wizard, leave the Netmask set to 24

6. Next to Networks, click the Add button.

7. Under the Network column, enter 172.31.101.0

8. Click Next

9. At Step 3 of 6, click the Add dropdown menu and select Add Infoblox Member

10. Click on the link for ibns1.techblue.net from the Member Selector window

11. Click Next after the Member info is populated

12. At Step 4 of 7, click the Override button in the section for Routers (this will change the button color to black and the button will now say Inherit)

13. Click the IP Address field in the Routers section

14. Enter the IP address for the router on this network – 172.31.101.1

15. Click Save & Close to save changes

Subtask 3.2 Solution: Creating a DHCPv4 range for clients

1. Login to NIOS GM web interface.

2. Navigate to Data Management → DHCP → Networks.

3. In the Go to field, type in 172.31.101 and click on the first match (172.31.101.0).

4. Open the network object 172.31.101.0/24 by clicking on Open (→)

   

5. Once inside 172.31.101.0/24, click + from the dropdown and choose Range.

6. Click Next for the first step of Add IPv4 Range Wizard (no templates available).

7. In step 2 provide Start and End IP addresses along with a name for the range. In our example below, we are creating a range of 61 addresses although the requirement is only for 50 clients. It is recommended to have 10-20% extra IP addresses in client ranges.

   

8. In Step 3, choose Grid Member and select ibns1.techblue.net from the drop-down.

   

9. Click Save and Close.

Subtask 3.3 Solution: Restarting Grid services

Changes made to the DHCP configuration during Network creation only take effect after a service restart.

1. Restart the DHCP Service by clicking the Restart button in the notification banner at the top of Grid Manager

2. At the Restart Grid Services window, click Restart

Alternatively, we can also restart services from the Members menu.

1. Navigate to Grid → Grid Manager → Members

2. Place a checkmark in the box beside ibns1.techblue.net

3. From the Toolbar on the right, click Restart Services

4. Select the radio button to Force service restart

5. Click Restart

A failover association is created by combining two DHCP servers into a failover pair.

1. Navigate to Data Management → DHCP → Members → IPv4 DHCP Failover Associations

2. Click on the Add (+) button

3. This action opens the Add IPv4 DHCP Failover Association Wizard

4. At Step 1 of 3, enter D1-D2 for Name

5. For DHCP Failover Primary, leave the radio button set to Grid Member and click the button for Select Member

6. Click the link for ibns1.techblue.net

7. For the DHCP Failover Secondary, leave the radio button set to Grid Member and click the button for Select Member

8. Click the link for ibns2.techblue.net

9. Click Save & Close

10. Place a check in the box beside the newly created D1-D2 entry and click Edit

11. Toggle advanced mode

12. Select the Failover Settings section and click the Advanced tab

13. Change the Maximum Client Lead Time(s) value to 300

14. Click Save & Close

The following configuration is for our testing purposes in the lab environment.
IN A PRODUCTION ENVIRONMENT, DO NOT CHANGE THE MCLT VALUE WITHOUT FIRST DISCUSSING WITH INFOBLOX SUPPORT

While creating a Network meant for DHCP failover, the important step is to assign both the failover peers to the Network Object.

1. Navigate to Data Management → DHCP → Networks → Networks → Networks Home

2. Click the Add dropdown menu and select IPv4 Network

3. Select the radio button for Add Network

4. Click Next

5. At Step 2 of 6, leave the Netmask set to 24

6. Next to Networks, click the Add button

7. Under the Network column, enter 172.31.111.0

8. Click Next

9. At Step 3 of 6, click the Add dropdown menu and select Add Infoblox Member, then click on the link for ibns1.techblue.net from the Member Selector window

10. Repeat the above action once more to also assign ibns2.techblue.net to the Network.

11. Click Next after both the Members are populated

12. At Step 4 of 7, click the Override button in the section for Routers (this will change the button color to black and the button will now say Inherit)

13. Click the IP Address field in the Routers section

14. Enter the IP address for the router on this network – 172.31.111.1

15. Click Save & Close to save changes
    

Note that the status of the failover association will display Failure until both networks and ranges have been assigned. This behavior is expected at the end of this task.

Subtask 6.1 Solution: Overriding inherited options

1. Navigate to Data Management → DHCP → Members → Members

2. Click the hamburger icon (=) next to ibns2 and choose Edit.

3. In the General section, scroll down to find Lease Time

4. Click Override and change the value to 15 minutes

5. Click Save and Close to save changes

Subtask 6.2 Solution: Restarting Grid services

Changes made to the DHCP configuration only take effect after a service restart.

1. Restart the DHCP Service by clicking the Restart button in the notification banner at the top of Grid Manager

2. At the Restart Grid Services window, click Restart

Subtask 6.3 Solution: Reading the DHCP member configuration

1. Navigate to Data Management → DHCP → Members → Members

2. Place a check mark in the box next to ibns2.techblue.net

3. From the Toolbar on the right, click View DHCP Configuration

4. Select IPv4(Disable pop up blocker)

5. In the configuration file, locate the value of default-lease-time, it should be 900 seconds equivalent to 15mins.

Subtask 7.1 Solution: Creating a DHCPv4 option

DHCP Option 150(rfc5859) is an IANA-recognized option, which is not included in the default DHCP Option Space in NIOS. Therefore, we need to create a new IPv4 DHCP option according to IANA specifications. The Option Name, Option Code and Data type are all defined in the RFC.

1. Navigate to Data Management → DHCP → Option Spaces

2. Place a check mark in the box beside DHCP and click Edit

   

3. Expand the DHCP (Option Space) window by clicking and dragging from the lower-right corner. This will make it easier to locate and add the necessary details in the following steps.

   

4. In the DHCP(Option Space) window, click the Add button

5. Scroll to the end of the list to find the blank entry

6. For Name, enter tftp-servers

7. For Code, enter 150

8. For Type, use the list to select array of ip-address

   

9. Click Save & Close

Subtask 7.2 Solution: Assigning the new option to Grid

Edit the DHCP Grid Properties and add 10.200.0.20 to the tftp-servers option for all IPv4 network

1. Navigate to Data Management → DHCP → Networks

2. From the Toolbar on the right, click Grid DHCP Properties

3. Select the section labeled IPv4 DHCP Options

4. Use the drop-down list for Custom DHCP Options to locate the entry for tftp-servers (150) (it will be at the very end of the list)

5. Enter 10.200.0.20 for the value

6. Click Save & Close

Subtask 7.3 Solution: Restarting Grid services

Changes made to the DHCP configuration only take effect after service restart.

1. Restart the DHCP Service by clicking the Restart button in the notification banner at the top of Grid Manager

2. At the Restart Grid Services window, click Restart

Subtask 8.1 Solution: Capture DHCP information

You need to find out what the client is sending in its DHCPDISCOVER message and find something that you can use to identify the client. Enable DHCP on the VM testing-linux, while performing traffic capture on the DHCP member ibns1.

Starting the traffic capture in the GM

Switch to the VM jump-desktop.

1. In the GM web interface, navigate to Grid→Grid Manager→Members.

2. From the Toolbar on the right, scroll down and click Traffic Capture, this brings out the Traffic Capture dialog.

3. In the Traffic Capture dialog, click the Add (+) button and select ibns1.techblue.net from the Member Selector window.

4. Verify that the the Interface for this is set to ALL (drop-down list).

5. Click the Capture Control Start button to start the capture.

   

6. If prompted about overwriting existing capture files, answer Yes.

7. Leave the Traffic Capture dialog open and continue to the next step.

Enabling DHCP in the test client

Switch to the VM testing-linux.

1. Open a Terminal window on the VM testing-linux.

2. Use the command sudo set-network-disable (sudo password: infoblox) to disable DHCP.

3. Use the command sudo clear-dhcp-leases to clear any previous leases.

4. Use the command sudo set-network-dhcp to re-enable DHCP.

5. Use the command sudo show-dhcp-lease to see the lease details. Below is an example of the output of this command:

   CODE

   --- Raw DHCP Lease Information
   lease {
     interface "ens160";
     fixed-address 172.31.101.79;
     option subnet-mask 255.255.255.0;
     option dhcp-lease-time 43200;
     option routers 172.31.101.1;
     option dhcp-message-type 5;
     option dhcp-server-identifier 10.100.0.105;
     option domain-name-servers 10.100.0.105,10.200.0.105;
     option domain-name "techblue.net";
     renew 5 2023/08/11 01:33:38;
     rebind 5 2023/08/11 06:19:36;
     expire 5 2023/08/11 07:49:36;
   }

Stopping the traffic capture in the GM

Switch to the VM jump-desktop.

1. Back in the Grid Manager, click the Stop button to halt traffic capture.

2. Place a checkmark beside ibns1.techblue.net.

3. Click the Download button.

4. If prompted, save the file to the Downloads folder. The filename will contain the name of the member, the word tcpdump, and has the file extension tar.gz.

While you are in the GM, you can also verify that you can see the client’s lease file under Data Management → DHCP → Leases.

Subtask 8.2 Solution: Analyze the captured traffic

Download and examine the traffic capture to locate relevant DHCP option information.

1. On the jump-desktop, open the Downloads folder.

2. Right-click on the packet capture file downloaded in Task 1 and choose Extract Here. This action creates a new folder in the Downloads folder.

3. Open the newly created folder and double click on the entry traffic.cap to open it with Wireshark.

4. In the Display Filter text field near the top, enter dhcp, and press the enter key to apply the filter. This hides all other packets, leaving only DHCP packets.

5. Locate the DHCPDISCOVER packet from the client. It should show the source address 10.100.0.1 (the router interface), destination address 10.100.0.105 (DHCP server), and in the Info section shows DHCP Discover followed by the transaction ID.

6. With the packet selected, scroll down and expand the Dynamic Host Configuration Protocol (Discover) section.

7. Scroll down further to expand DHCP options to examine. Some common options that can be used to identify the client are: Option 12 (Host Name), Option 55 (Parameter Request List, or PRL), and Option 60 (Vendor class identifier).

8. Expand Option 60. You can see the string IBEDU.sauron-2022_10_21 (example shown below.)

   

9. Note this string down. You will use this to create an DHCP option filter later.

Subtask 8.3 Solution: Create a new IPv4 option space

Since the device requires DHCP option numbers (10 and 15) that conflict with existing ones, we must create a new IPv4 option space. Create a new space named Tolkien, and create the following 2 DHCP options according to the vendor’s documentation listed in Table 2532-1:

1. In GM web interface, navigate to Data Management→DHCP→Option Spaces.

2. Click the Add drop-down button and choose IPv4 Option Space. The Add IPv4 Option Space Wizard appears.

3. For Name, enter Tolkien.

4. Click the Add button to create a new option (Information taken from Table 2532-1):

   • Name: ConfigFile

   • Code: 10

   • Type: text

5. Click the Add button again to create another new option:

   • Name: ControllerIP

   • Code: 15

   • Type: array of ip-address

6. The end screen should look like this:

   

7. Click Save & Close.

Subtask 8.4 Solution: Create an IPv4 option filter

Create an IPv4 Option Filter called Tolkien Filter. This filter will search for an Option 60 value from all clients. If a match is found, the DHCP server will return options in the standard DHCPv4 option space as well as the newly created Tolkien option space.

1. Navigate to Data Management→DHCP→Filters.

2. Click Add → IPv4 Option Filter. This brings out the Add IPv4 Option Filter Wizard.

3. In Step 1 of 5 of the Wizard, for the filter Name, enter Tolkien Filter.

4. Ensure Apply this filter as a global DHCP class is checked. This will apply the filter to every incoming DHCP message.

5. At Step 2 of 5 of the Wizard, create a rule that matches for any vendor-class-identifier string that begins with IBEDU:

   • In the drop-down menu Choose Filter, select vendor-class-identifier (60) string.

   • In the drop-down menu Choose Operator, select substring equals, set the offset to 0 and length to 5.

   • In the value field, enter IBEDU. Click Next.

     

6. At Step 3 of 5 of the Wizard, in the Option Space drop-down menu, select DHCP+Tolkien.

   

7. Click Save & Close.

8. Restart services when prompted.

In Step 2 of 5 of the Add IPv4 Option Filter Wizard, We are matching for just the first five letters of Option 60, IBEDU, rather than the entire string, IBEDU.sauron-2022_10_21. You can certainly match for the entire string, especially if you are looking to match for specific model numbers. In our example here, this closely resembles matching for the make or product family, rather than the specific model.

Subtask 8.5 Solution: Check if the Vendor Options Are Provided

1. Open a Terminal window on the VM testing-linux.

2. Use the command sudo set-network-disable (sudo password: infoblox) to disable DHCP.

3. Use the command sudo clear-dhcp-leases to clear any previous leases.

4. Use the command sudo set-network-dhcp to re-enable DHCP.

5. Use the command sudo show-dhcp-lease to see the lease details.

6. The output should follow a format similar to the example below:

   CODE

   --- Raw DHCP Lease Information
   
   lease {
     interface "ens160";
     fixed-address 172.31.101.85;
     option subnet-mask 255.255.255.0;
     option dhcp-lease-time 43200;
     option routers 172.31.101.1;
     option dhcp-message-type 5;
     option dhcp-server-identifier 10.100.0.105;
     option domain-name-servers 10.100.0.105,10.200.0.105;
     option domain-name "techblue.net";
     renew 5 2023/08/11 01:33:38;
     rebind 5 2023/08/11 06:19:36;
     expire 5 2023/08/11 07:49:36;
   }

7. The lease should NOT contain the expected vendor options (such as option 10 and option 15). Proceed with troubleshooting in Subtask 8.6.

Subtask 8.6 Solution: Troubleshoot DHCP Custom Vendor Option delivery

Review the DHCP Member Configuration

1. Switch to the VM jump-desktop and Navigate to Data Management → DHCP → Member on Grid Manager UI.

   • Select ibns1.techblue.net, the DHCP member serving 172.31.101.0/24.

   • Click Toolbar → View DHCP Configuration → IPv4.

   • Verify that the option space Tolkien is properly setup. However, these option values are not specified in the network 172.31.101.0/24.

Check Network-Specific DHCP Options

1. Navigate to Data Management → DHCP → Networks → Networks.

   • Select 172.31.101.0/24, then click Edit.

   • Open the IPv4 DHCP Options tab.

   • Under Custom DHCP Options, verify if the expected options are configured.

Observations

• The option space is defined at the member level, but the required options are missing for the 172.31.101.0/24 network.

• The Custom DHCP Options fields only contain tftp-servers , confirming the missing configuration.

  

Subtask 8.7 Solution: Add the DHCP options to the network

Edit the 172.31.101.0/24 network and configure values for the newly defined custom DHCP options.

1. Navigate to Data Management → DHCP → Networks → Networks.

2. Select 172.31.101.0/24, and click Edit.

3. Select the IPv4 DHCP Options tab on the left.

4. Scroll down to the bottom to the Custom DHCP Options section.

5. Scroll all the way to the bottom of the list to add a new Custom DHCP Option

6. Configure the first custom option (option 10):

   • Use the drop-down menu to select the DHCP option space Tolkien.

   • Use the drop-down menu to select ConfigFile (10) text.

   • In the text field, enter bootfile.cfg.

7. Click the plus (+) button to add another custom option (option 15):

   • Use the drop-down menu to select the DHCP option space Tolkien.

   • Use the drop-down menu to select ControllerIP (15) array of ip-address.

   • In the text field, enter 10.100.52.52.

8. The configuration should look like this:

   

9. Click Save & Close.

10. Restart services when prompted.

Subtask 8.8 Solution: Verify the client behavior

Switch to the VM testing-linux.

1. Open a Terminal window on the VM testing-linux.

2. Use the command sudo set-network-disable (sudo password: infoblox) to disable DHCP.

3. Use the command sudo clear-dhcp-leases to clear any previous leases.

4. Use the command sudo set-network-dhcp to re-enable DHCP.

5. Use the command sudo show-dhcp-lease to see the lease details. You should be able to see additional vendor encapsulated options (option 43) information near the bottom like this:

-- Encapsulated DHCP Options (vendor-encapsulated-options)

Decoding part 1: a:c:62:6f:6f:74:66:69:6c:65:2e:63:66:67:f:4
Option ID: 10
Option length: 12
Option value: "bootfile.cfg"

Decoding part 2: f:4:a:64:34:34
Option ID: 15
Option length: 4
Option value: "10.100.52.52"