Check-Mac-Address

These scenarios show how the check-mac-address feature works for the DHCP server

../../../_images/check-mac-address.svg

Test Check MAC Address

Description

The check-mac-address option filters packets if there are differences between the MAC address found at the ethernet header and the MAC address found in the DHCP packet. To check this option, you should send packets with these differences and enable this option to see if warnings appear in your logs. Also, this test checks how the server behaves under normal conditions.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces ethernet eth0 address 10.0.0.1/24
set service dhcp-server shared-network dhcp subnet 10.0.0.0/24 start 10.0.0.5 stop 10.0.0.5
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Run command system journal show | tail at DUT0 and check if output contains the following tokens:

DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Show output
Oct 30 12:29:14.379916 osdx OSDxCLI[101074]: User 'admin' added a new cfg line: 'show working'.
Oct 30 12:29:14.526807 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Oct 30 12:29:14.623131 osdx systemd[1]: Started dhcpd@main.service - "DHCP Server Service instance main".
Oct 30 12:29:14.624923 osdx cfgd[1636]: [101074]Completed change to active configuration
Oct 30 12:29:14.627671 osdx dhcpd[279778]: Wrote 0 leases to leases file.
Oct 30 12:29:14.650908 osdx OSDxCLI[101074]: User 'admin' committed the configuration.
Oct 30 12:29:14.667744 osdx OSDxCLI[101074]: User 'admin' left the configuration menu.
Oct 30 12:29:14.690942 osdx dhcpd[279778]: Server starting service.
Oct 30 12:29:14.800663 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 30 12:29:15.414687 osdx dhcpd[279778]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0

Step 3: Modify the following configuration lines in DUT0:

set service dhcp-server check-mac-address

Step 4: Run command system journal clear at DUT0.

Step 5: Run command system journal show | tail at DUT0 and check if output does not contain the following tokens:

DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Show output
Oct 30 12:29:16.527614 osdx systemd-journald[1923]: Runtime Journal (/run/log/journal/877522c656344df9b9ad28416f5f036f) is 2.0M, max 15.3M, 13.3M free.
Oct 30 12:29:16.530798 osdx systemd-journald[1923]: Received client request to rotate journal, rotating.
Oct 30 12:29:16.530848 osdx systemd-journald[1923]: Vacuuming done, freed 0B of archived journals from /run/log/journal/877522c656344df9b9ad28416f5f036f.
Oct 30 12:29:16.537315 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal clear'.

Step 6: Run command system journal show | tail at DUT0 and check if output contains the following tokens:

MAC received in DHCP packet (10:00:00:00:00:02) is different than source MAC in ethernet header (10:00:00:00:00:01)
Show output
Oct 30 12:29:16.527614 osdx systemd-journald[1923]: Runtime Journal (/run/log/journal/877522c656344df9b9ad28416f5f036f) is 2.0M, max 15.3M, 13.3M free.
Oct 30 12:29:16.530798 osdx systemd-journald[1923]: Received client request to rotate journal, rotating.
Oct 30 12:29:16.530848 osdx systemd-journald[1923]: Vacuuming done, freed 0B of archived journals from /run/log/journal/877522c656344df9b9ad28416f5f036f.
Oct 30 12:29:16.537315 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal clear'.
Oct 30 12:29:16.600695 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 30 12:29:16.702135 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 30 12:29:17.522623 osdx dhcpd[279827]: MAC received in DHCP packet (10:00:00:00:00:02) is different than source MAC in ethernet header (10:00:00:00:00:01)

Step 7: Set the following configuration in DUT1:

set interfaces ethernet eth0 mac '10:00:00:00:00:05'
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 8: Modify the following configuration lines in DUT1:

set interfaces ethernet eth0 address dhcp

Step 9: Run command interfaces ethernet eth0 show at DUT1 and check if output contains the following tokens:

10.0.0.5
Show output
-----------------------------------------------------------------
Name           IP Address           Admin  Oper  Vrf  Description
-----------------------------------------------------------------
eth0  10.0.0.5/24                   up     up
      fe80::dcad:beff:feef:6c10/64

Step 10: Run command service dhcp-server show leases main | grep 10.0.0.5 at DUT0 and check if output contains the following tokens:

10:00:00:00:00:05
Show output
10.0.0.5   10:00:00:00:00:05  2024/10/30 12:29:19  2024/10/31 00:29:19  2024/10/30 12:29:19

Test Check MAC Address VRF

Description

This scenario configures a DHCP server with VRF instead of regular interfaces and checks the check-mac-address option. To check this option, you will need to send packets with differences in the Source MAC for the link layer and the client MAC from the application layer.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces ethernet eth0 address 10.0.0.1/24
set interfaces ethernet eth0 vrf VRF0
set service dhcp-server shared-network dhcp local-vrf VRF0
set service dhcp-server shared-network dhcp subnet 10.0.0.0/24 start 10.0.0.5 stop 10.0.0.6
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'
set system vrf VRF0

Step 2: Run command system journal show | tail at DUT0 and check if output contains the following tokens:

DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Show output
Oct 30 12:29:25.792197 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Oct 30 12:29:25.860201 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Oct 30 12:29:25.980688 osdx systemd[1]: Started dhcpd@VRF0.service - "DHCP Server Service instance VRF0".
Oct 30 12:29:25.982373 osdx cfgd[1636]: [101074]Completed change to active configuration
Oct 30 12:29:25.982994 osdx dhcpd[280100]: Wrote 0 leases to leases file.
Oct 30 12:29:26.009375 osdx OSDxCLI[101074]: User 'admin' committed the configuration.
Oct 30 12:29:26.038835 osdx OSDxCLI[101074]: User 'admin' left the configuration menu.
Oct 30 12:29:26.064337 osdx dhcpd[280100]: Server starting service.
Oct 30 12:29:26.178005 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 30 12:29:26.443593 osdx dhcpd[280100]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0

Step 3: Modify the following configuration lines in DUT0:

set service dhcp-server check-mac-address

Step 4: Run command system journal clear at DUT0.

Step 5: Run command system journal show | tail at DUT0 and check if output does not contain the following tokens:

DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Show output
Oct 30 12:29:27.931082 osdx systemd-journald[1923]: Runtime Journal (/run/log/journal/877522c656344df9b9ad28416f5f036f) is 2.0M, max 15.3M, 13.3M free.
Oct 30 12:29:27.932199 osdx systemd-journald[1923]: Received client request to rotate journal, rotating.
Oct 30 12:29:27.932251 osdx systemd-journald[1923]: Vacuuming done, freed 0B of archived journals from /run/log/journal/877522c656344df9b9ad28416f5f036f.
Oct 30 12:29:27.941882 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal clear'.

Step 6: Run command system journal show | tail at DUT0 and check if output contains the following tokens:

MAC received in DHCP packet (10:00:00:00:00:02) is different than source MAC in ethernet header (10:00:00:00:00:01)
Show output
Oct 30 12:29:27.931082 osdx systemd-journald[1923]: Runtime Journal (/run/log/journal/877522c656344df9b9ad28416f5f036f) is 2.0M, max 15.3M, 13.3M free.
Oct 30 12:29:27.932199 osdx systemd-journald[1923]: Received client request to rotate journal, rotating.
Oct 30 12:29:27.932251 osdx systemd-journald[1923]: Vacuuming done, freed 0B of archived journals from /run/log/journal/877522c656344df9b9ad28416f5f036f.
Oct 30 12:29:27.941882 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal clear'.
Oct 30 12:29:28.006025 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 30 12:29:28.118014 osdx OSDxCLI[101074]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 30 12:29:28.531527 osdx dhcpd[280149]: MAC received in DHCP packet (10:00:00:00:00:02) is different than source MAC in ethernet header (10:00:00:00:00:01)

Step 7: Set the following configuration in DUT1:

set interfaces ethernet eth0 mac '10:00:00:00:00:05'
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 8: Modify the following configuration lines in DUT1:

set interfaces ethernet eth0 address dhcp

Step 9: Run command interfaces ethernet eth0 show at DUT1 and check if output contains the following tokens:

10.0.0.5
Show output
-----------------------------------------------------------------
Name           IP Address           Admin  Oper  Vrf  Description
-----------------------------------------------------------------
eth0  10.0.0.5/24                   up     up
      fe80::dcad:beff:feef:6c10/64

Step 10: Run command service dhcp-server show leases VRF0 | grep 10.0.0.5 at DUT0 and check if output contains the following tokens:

10:00:00:00:00:05
Show output
10.0.0.5   10:00:00:00:00:05  2024/10/30 12:29:31  2024/10/31 00:29:31  2024/10/30 12:29:31