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
Jan 10 12:45:02.489845 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Jan 10 12:45:02.618217 osdx systemd[1]: Started dhcpd@main.service - "DHCP Server Service instance main".
Jan 10 12:45:02.619735 osdx cfgd[1445]: [39537]Completed change to active configuration
Jan 10 12:45:02.620614 osdx dhcpd[61156]: Wrote 0 leases to leases file.
Jan 10 12:45:02.650729 osdx OSDxCLI[39537]: User 'admin' committed the configuration.
Jan 10 12:45:02.666467 osdx OSDxCLI[39537]: User 'admin' left the configuration menu.
Jan 10 12:45:02.669979 osdx dhcpd[61156]: Server starting service.
Jan 10 12:45:02.801314 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal show | tail'.
Jan 10 12:45:02.852630 osdx dhcpd[61156]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Jan 10 12:45:03.853246 osdx dhcpd[61156]: 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
Jan 10 12:45:04.617610 osdx systemd-journald[1741]: Runtime Journal (/run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71) is 2.0M, max 15.3M, 13.3M free.
Jan 10 12:45:04.618047 osdx systemd-journald[1741]: Received client request to rotate journal, rotating.
Jan 10 12:45:04.618076 osdx systemd-journald[1741]: Vacuuming done, freed 0B of archived journals from /run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71.
Jan 10 12:45:04.626572 osdx OSDxCLI[39537]: 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
Jan 10 12:45:04.617610 osdx systemd-journald[1741]: Runtime Journal (/run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71) is 2.0M, max 15.3M, 13.3M free.
Jan 10 12:45:04.618047 osdx systemd-journald[1741]: Received client request to rotate journal, rotating.
Jan 10 12:45:04.618076 osdx systemd-journald[1741]: Vacuuming done, freed 0B of archived journals from /run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71.
Jan 10 12:45:04.626572 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal clear'.
Jan 10 12:45:04.687877 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal show | tail'.
Jan 10 12:45:04.789156 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal show | tail'.
Jan 10 12:45:04.940730 osdx dhcpd[61206]: 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  2025/01/10 12:45:07  2025/01/11 00:45:07  2025/01/10 12:45:07

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
Jan 10 12:45:13.691138 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Jan 10 12:45:13.755141 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Jan 10 12:45:13.835404 osdx systemd[1]: Started dhcpd@VRF0.service - "DHCP Server Service instance VRF0".
Jan 10 12:45:13.837004 osdx cfgd[1445]: [39537]Completed change to active configuration
Jan 10 12:45:13.838337 osdx dhcpd[61515]: Wrote 0 leases to leases file.
Jan 10 12:45:13.863948 osdx OSDxCLI[39537]: User 'admin' committed the configuration.
Jan 10 12:45:13.879941 osdx OSDxCLI[39537]: User 'admin' left the configuration menu.
Jan 10 12:45:13.895227 osdx dhcpd[61515]: Server starting service.
Jan 10 12:45:14.014134 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal show | tail'.
Jan 10 12:45:14.440977 osdx dhcpd[61515]: 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
Jan 10 12:45:15.751255 osdx systemd-journald[1741]: Runtime Journal (/run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71) is 2.0M, max 15.3M, 13.3M free.
Jan 10 12:45:15.755117 osdx systemd-journald[1741]: Received client request to rotate journal, rotating.
Jan 10 12:45:15.755159 osdx systemd-journald[1741]: Vacuuming done, freed 0B of archived journals from /run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71.
Jan 10 12:45:15.760207 osdx OSDxCLI[39537]: 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
Jan 10 12:45:15.751255 osdx systemd-journald[1741]: Runtime Journal (/run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71) is 2.0M, max 15.3M, 13.3M free.
Jan 10 12:45:15.755117 osdx systemd-journald[1741]: Received client request to rotate journal, rotating.
Jan 10 12:45:15.755159 osdx systemd-journald[1741]: Vacuuming done, freed 0B of archived journals from /run/log/journal/fda2548b09bd4d8ba0d8cad09b8eab71.
Jan 10 12:45:15.760207 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal clear'.
Jan 10 12:45:15.821447 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal show | tail'.
Jan 10 12:45:15.916720 osdx OSDxCLI[39537]: User 'admin' executed a new command: 'system journal show | tail'.
Jan 10 12:45:16.533204 osdx dhcpd[61565]: 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  2025/01/10 12:45:19  2025/01/11 00:45:19  2025/01/10 12:45:19