Check-Mac-Address

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

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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
Nov 12 15:54:02.655909 osdx cfgd[1666]: [123608]Completed change to active configuration
Nov 12 15:54:02.656752 osdx dhcpd[127918]: Wrote 0 leases to leases file.
Nov 12 15:54:02.667793 osdx OSDxCLI[123608]: User 'admin' committed the configuration.
Nov 12 15:54:02.678078 osdx dhcpd[127918]: Server starting service.
Nov 12 15:54:02.683927 osdx OSDxCLI[123608]: User 'admin' left the configuration menu.
Nov 12 15:54:02.819054 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal show | tail'.
Nov 12 15:54:03.667564 osdx dhcpd[127918]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Nov 12 15:54:04.668004 osdx dhcpd[127918]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Nov 12 15:54:04.723489 osdx dhcpd[127918]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Nov 12 15:54:04.723516 osdx dhcpd[127918]: DHCPOFFER on 10.0.0.5 to 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
Nov 12 15:54:05.621472 osdx systemd-journald[1872]: Runtime Journal (/run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99) is 1.8M, max 13.8M, 11.9M free.
Nov 12 15:54:05.621946 osdx systemd-journald[1872]: Received client request to rotate journal, rotating.
Nov 12 15:54:05.622008 osdx systemd-journald[1872]: Vacuuming done, freed 0B of archived journals from /run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99.
Nov 12 15:54:05.630948 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal clear'.
Nov 12 15:54:05.638224 osdx dhcpd[127976]: Server starting service.

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
Nov 12 15:54:05.621472 osdx systemd-journald[1872]: Runtime Journal (/run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99) is 1.8M, max 13.8M, 11.9M free.
Nov 12 15:54:05.621946 osdx systemd-journald[1872]: Received client request to rotate journal, rotating.
Nov 12 15:54:05.622008 osdx systemd-journald[1872]: Vacuuming done, freed 0B of archived journals from /run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99.
Nov 12 15:54:05.630948 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal clear'.
Nov 12 15:54:05.638224 osdx dhcpd[127976]: Server starting service.
Nov 12 15:54:05.694139 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal show | tail'.
Nov 12 15:54:05.795517 osdx dhcpd[127976]: 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  2025/11/12 15:54:08  2025/11/13 03:54:08  2025/11/12 15:54:08

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
Nov 12 15:54:15.608675 osdx cfgd[1666]: [123608]Completed change to active configuration
Nov 12 15:54:15.609289 osdx dhcpd[128327]: Wrote 0 leases to leases file.
Nov 12 15:54:15.620556 osdx OSDxCLI[123608]: User 'admin' committed the configuration.
Nov 12 15:54:15.630794 osdx dhcpd[128327]: Server starting service.
Nov 12 15:54:15.637586 osdx OSDxCLI[123608]: User 'admin' left the configuration menu.
Nov 12 15:54:15.770693 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal show | tail'.
Nov 12 15:54:16.155757 osdx dhcpd[128327]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Nov 12 15:54:17.156697 osdx dhcpd[128327]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Nov 12 15:54:17.219715 osdx dhcpd[128327]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Nov 12 15:54:17.219742 osdx dhcpd[128327]: DHCPOFFER on 10.0.0.5 to 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
Nov 12 15:54:18.520152 osdx systemd-journald[1872]: Runtime Journal (/run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99) is 1.8M, max 13.8M, 11.9M free.
Nov 12 15:54:18.522659 osdx systemd-journald[1872]: Received client request to rotate journal, rotating.
Nov 12 15:54:18.522722 osdx systemd-journald[1872]: Vacuuming done, freed 0B of archived journals from /run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99.
Nov 12 15:54:18.530408 osdx OSDxCLI[123608]: 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
Nov 12 15:54:18.520152 osdx systemd-journald[1872]: Runtime Journal (/run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99) is 1.8M, max 13.8M, 11.9M free.
Nov 12 15:54:18.522659 osdx systemd-journald[1872]: Received client request to rotate journal, rotating.
Nov 12 15:54:18.522722 osdx systemd-journald[1872]: Vacuuming done, freed 0B of archived journals from /run/log/journal/04bdf7f70d714c0fb0ef3d9377529e99.
Nov 12 15:54:18.530408 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal clear'.
Nov 12 15:54:18.595350 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal show | tail'.
Nov 12 15:54:18.697824 osdx OSDxCLI[123608]: User 'admin' executed a new command: 'system journal show | tail'.
Nov 12 15:54:19.343896 osdx dhcpd[128383]: 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)
Nov 12 15:54:20.395926 osdx dhcpd[128383]: 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  2025/11/12 15:54:22  2025/11/13 03:54:22  2025/11/12 15:54:22