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
Jul 03 16:49:17.370835 osdx OSDxCLI[337548]: User 'admin' added a new cfg line: 'show working'.
Jul 03 16:49:17.483582 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Jul 03 16:49:17.567862 osdx systemd[1]: Started dhcpd@main.service - "DHCP Server Service instance main".
Jul 03 16:49:17.569539 osdx cfgd[1440]: [337548]Completed change to active configuration
Jul 03 16:49:17.571546 osdx dhcpd[348738]: Wrote 0 leases to leases file.
Jul 03 16:49:17.571686 osdx OSDxCLI[337548]: User 'admin' committed the configuration.
Jul 03 16:49:17.605082 osdx OSDxCLI[337548]: User 'admin' left the configuration menu.
Jul 03 16:49:17.627692 osdx dhcpd[348738]: Server starting service.
Jul 03 16:49:17.750511 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 03 16:49:18.479787 osdx dhcpd[348738]: 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
Jul 03 16:49:19.412416 osdx systemd-journald[19587]: Runtime Journal (/run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b) is 2.0M, max 15.3M, 13.2M free.
Jul 03 16:49:19.415591 osdx systemd-journald[19587]: Received client request to rotate journal, rotating.
Jul 03 16:49:19.415645 osdx systemd-journald[19587]: Vacuuming done, freed 0B of archived journals from /run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b.
Jul 03 16:49:19.423428 osdx OSDxCLI[337548]: 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
Jul 03 16:49:19.412416 osdx systemd-journald[19587]: Runtime Journal (/run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b) is 2.0M, max 15.3M, 13.2M free.
Jul 03 16:49:19.415591 osdx systemd-journald[19587]: Received client request to rotate journal, rotating.
Jul 03 16:49:19.415645 osdx systemd-journald[19587]: Vacuuming done, freed 0B of archived journals from /run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b.
Jul 03 16:49:19.423428 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal clear'.
Jul 03 16:49:19.488093 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 03 16:49:19.511760 osdx dhcpd[348781]: 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:6c20/64

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  2024/07/03 16:49:21  2024/07/04 04:49:21  2024/07/03 16:49:21

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
Jul 03 16:49:27.847782 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Jul 03 16:49:27.867780 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Jul 03 16:49:27.928245 osdx systemd[1]: Started dhcpd@VRF0.service - "DHCP Server Service instance VRF0".
Jul 03 16:49:27.930022 osdx cfgd[1440]: [337548]Completed change to active configuration
Jul 03 16:49:27.932038 osdx dhcpd[349014]: Wrote 0 leases to leases file.
Jul 03 16:49:27.932960 osdx OSDxCLI[337548]: User 'admin' committed the configuration.
Jul 03 16:49:27.954065 osdx OSDxCLI[337548]: User 'admin' left the configuration menu.
Jul 03 16:49:27.967928 osdx dhcpd[349014]: Server starting service.
Jul 03 16:49:28.090322 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 03 16:49:28.211825 osdx dhcpd[349014]: 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
Jul 03 16:49:29.854790 osdx systemd-journald[19587]: Runtime Journal (/run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b) is 2.0M, max 15.3M, 13.3M free.
Jul 03 16:49:29.855768 osdx systemd-journald[19587]: Received client request to rotate journal, rotating.
Jul 03 16:49:29.855817 osdx systemd-journald[19587]: Vacuuming done, freed 0B of archived journals from /run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b.
Jul 03 16:49:29.864573 osdx OSDxCLI[337548]: 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
Jul 03 16:49:29.854790 osdx systemd-journald[19587]: Runtime Journal (/run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b) is 2.0M, max 15.3M, 13.3M free.
Jul 03 16:49:29.855768 osdx systemd-journald[19587]: Received client request to rotate journal, rotating.
Jul 03 16:49:29.855817 osdx systemd-journald[19587]: Vacuuming done, freed 0B of archived journals from /run/log/journal/aa1bd7befff24a8b91d1e90ef92c032b.
Jul 03 16:49:29.864573 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal clear'.
Jul 03 16:49:29.929384 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 03 16:49:30.049715 osdx OSDxCLI[337548]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 03 16:49:30.291618 osdx dhcpd[349057]: 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:6c20/64

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  2024/07/03 16:49:33  2024/07/04 04:49:33  2024/07/03 16:49:33