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
Apr 06 14:11:59.278793 osdx cfgd[1666]: [2283]Completed change to active configuration
Apr 06 14:11:59.279267 osdx dhcpd[8441]: Wrote 0 leases to leases file.
Apr 06 14:11:59.290153 osdx OSDxCLI[2283]: User 'admin' committed the configuration.
Apr 06 14:11:59.314936 osdx OSDxCLI[2283]: User 'admin' left the configuration menu.
Apr 06 14:11:59.320840 osdx dhcpd[8441]: Server starting service.
Apr 06 14:11:59.471989 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal show | tail'.
Apr 06 14:12:00.206568 osdx dhcpd[8441]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Apr 06 14:12:01.207081 osdx dhcpd[8441]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Apr 06 14:12:01.262736 osdx dhcpd[8441]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Apr 06 14:12:01.262768 osdx dhcpd[8441]: 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
Apr 06 14:12:02.215770 osdx systemd-journald[1969]: Runtime Journal (/run/log/journal/8555dfc266884f30a3544832475c4d6c) is 1.9M, max 13.8M, 11.8M free.
Apr 06 14:12:02.216697 osdx systemd-journald[1969]: Received client request to rotate journal, rotating.
Apr 06 14:12:02.216749 osdx systemd-journald[1969]: Vacuuming done, freed 0B of archived journals from /run/log/journal/8555dfc266884f30a3544832475c4d6c.
Apr 06 14:12:02.227568 osdx OSDxCLI[2283]: 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
Apr 06 14:12:02.215770 osdx systemd-journald[1969]: Runtime Journal (/run/log/journal/8555dfc266884f30a3544832475c4d6c) is 1.9M, max 13.8M, 11.8M free.
Apr 06 14:12:02.216697 osdx systemd-journald[1969]: Received client request to rotate journal, rotating.
Apr 06 14:12:02.216749 osdx systemd-journald[1969]: Vacuuming done, freed 0B of archived journals from /run/log/journal/8555dfc266884f30a3544832475c4d6c.
Apr 06 14:12:02.227568 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal clear'.
Apr 06 14:12:02.292516 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal show | tail'.
Apr 06 14:12:02.322748 osdx dhcpd[8500]: 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  2026/04/06 14:12:04  2026/04/07 02:12:04  2026/04/06 14:12:04

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
Apr 06 14:12:11.517541 osdx cfgd[1666]: [2283]Completed change to active configuration
Apr 06 14:12:11.518011 osdx dhcpd[8851]: Wrote 0 leases to leases file.
Apr 06 14:12:11.529533 osdx OSDxCLI[2283]: User 'admin' committed the configuration.
Apr 06 14:12:11.545869 osdx OSDxCLI[2283]: User 'admin' left the configuration menu.
Apr 06 14:12:11.559886 osdx dhcpd[8851]: Server starting service.
Apr 06 14:12:11.689980 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal show | tail'.
Apr 06 14:12:12.177140 osdx dhcpd[8851]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Apr 06 14:12:13.178130 osdx dhcpd[8851]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Apr 06 14:12:13.229750 osdx dhcpd[8851]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Apr 06 14:12:13.229783 osdx dhcpd[8851]: 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
Apr 06 14:12:14.373636 osdx systemd-journald[1969]: Runtime Journal (/run/log/journal/8555dfc266884f30a3544832475c4d6c) is 1.8M, max 13.8M, 11.9M free.
Apr 06 14:12:14.375753 osdx systemd-journald[1969]: Received client request to rotate journal, rotating.
Apr 06 14:12:14.375818 osdx systemd-journald[1969]: Vacuuming done, freed 0B of archived journals from /run/log/journal/8555dfc266884f30a3544832475c4d6c.
Apr 06 14:12:14.384026 osdx OSDxCLI[2283]: 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
Apr 06 14:12:14.373636 osdx systemd-journald[1969]: Runtime Journal (/run/log/journal/8555dfc266884f30a3544832475c4d6c) is 1.8M, max 13.8M, 11.9M free.
Apr 06 14:12:14.375753 osdx systemd-journald[1969]: Received client request to rotate journal, rotating.
Apr 06 14:12:14.375818 osdx systemd-journald[1969]: Vacuuming done, freed 0B of archived journals from /run/log/journal/8555dfc266884f30a3544832475c4d6c.
Apr 06 14:12:14.384026 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal clear'.
Apr 06 14:12:14.447627 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal show | tail'.
Apr 06 14:12:14.551072 osdx OSDxCLI[2283]: User 'admin' executed a new command: 'system journal show | tail'.
Apr 06 14:12:15.373001 osdx dhcpd[8907]: 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)
Apr 06 14:12:16.432940 osdx dhcpd[8907]: 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  2026/04/06 14:12:18  2026/04/07 02:12:18  2026/04/06 14:12:18