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
May 26 11:48:21.741024 osdx cfgd[1653]: [29144]Completed change to active configuration
May 26 11:48:21.741906 osdx dhcpd[34468]: Wrote 0 leases to leases file.
May 26 11:48:21.769070 osdx OSDxCLI[29144]: User 'admin' committed the configuration.
May 26 11:48:21.779208 osdx dhcpd[34468]: Server starting service.
May 26 11:48:21.797206 osdx OSDxCLI[29144]: User 'admin' left the configuration menu.
May 26 11:48:21.963450 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal show | tail'.
May 26 11:48:22.566712 osdx dhcpd[34468]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
May 26 11:48:23.567715 osdx dhcpd[34468]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
May 26 11:48:23.622677 osdx dhcpd[34468]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
May 26 11:48:23.622702 osdx dhcpd[34468]: 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
May 26 11:48:24.667209 osdx systemd-journald[1847]: Runtime Journal (/run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8) is 2.0M, max 15.3M, 13.2M free.
May 26 11:48:24.671084 osdx systemd-journald[1847]: Received client request to rotate journal, rotating.
May 26 11:48:24.671135 osdx systemd-journald[1847]: Vacuuming done, freed 0B of archived journals from /run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8.
May 26 11:48:24.678680 osdx OSDxCLI[29144]: 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
May 26 11:48:24.667209 osdx systemd-journald[1847]: Runtime Journal (/run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8) is 2.0M, max 15.3M, 13.2M free.
May 26 11:48:24.671084 osdx systemd-journald[1847]: Received client request to rotate journal, rotating.
May 26 11:48:24.671135 osdx systemd-journald[1847]: Vacuuming done, freed 0B of archived journals from /run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8.
May 26 11:48:24.678680 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal clear'.
May 26 11:48:24.744726 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal show | tail'.
May 26 11:48:24.878563 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal show | tail'.
May 26 11:48:25.714797 osdx dhcpd[34518]: 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)
May 26 11:48:26.766767 osdx dhcpd[34518]: 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  2025/05/26 11:48:29  2025/05/26 23:48:29  2025/05/26 11:48:29

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
May 26 11:48:37.099307 osdx cfgd[1653]: [29144]Completed change to active configuration
May 26 11:48:37.100151 osdx dhcpd[34816]: Wrote 0 leases to leases file.
May 26 11:48:37.126847 osdx OSDxCLI[29144]: User 'admin' committed the configuration.
May 26 11:48:37.145644 osdx OSDxCLI[29144]: User 'admin' left the configuration menu.
May 26 11:48:37.164926 osdx dhcpd[34816]: Server starting service.
May 26 11:48:37.288103 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal show | tail'.
May 26 11:48:37.508145 osdx dhcpd[34816]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
May 26 11:48:38.508373 osdx dhcpd[34816]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
May 26 11:48:38.567930 osdx dhcpd[34816]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
May 26 11:48:38.567957 osdx dhcpd[34816]: 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
May 26 11:48:40.026690 osdx systemd-journald[1847]: Runtime Journal (/run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8) is 2.0M, max 15.3M, 13.3M free.
May 26 11:48:40.028751 osdx systemd-journald[1847]: Received client request to rotate journal, rotating.
May 26 11:48:40.028826 osdx systemd-journald[1847]: Vacuuming done, freed 0B of archived journals from /run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8.
May 26 11:48:40.039366 osdx OSDxCLI[29144]: 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
May 26 11:48:40.026690 osdx systemd-journald[1847]: Runtime Journal (/run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8) is 2.0M, max 15.3M, 13.3M free.
May 26 11:48:40.028751 osdx systemd-journald[1847]: Received client request to rotate journal, rotating.
May 26 11:48:40.028826 osdx systemd-journald[1847]: Vacuuming done, freed 0B of archived journals from /run/log/journal/f6c1fe6bbcb147bb817825fa9dee7ff8.
May 26 11:48:40.039366 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal clear'.
May 26 11:48:40.122234 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal show | tail'.
May 26 11:48:40.193472 osdx OSDxCLI[29144]: User 'admin' executed a new command: 'system journal show | tail'.
May 26 11:48:40.667783 osdx dhcpd[34866]: 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)
May 26 11:48:41.723764 osdx dhcpd[34866]: 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  2025/05/26 11:48:44  2025/05/26 23:48:44  2025/05/26 11:48:44