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
Mar 18 11:27:38.123124 osdx cfgd[1456]: [6731]Completed change to active configuration
Mar 18 11:27:38.124589 osdx dhcpd[13904]: Wrote 0 leases to leases file.
Mar 18 11:27:38.165535 osdx OSDxCLI[6731]: User 'admin' committed the configuration.
Mar 18 11:27:38.197316 osdx OSDxCLI[6731]: User 'admin' left the configuration menu.
Mar 18 11:27:38.204044 osdx dhcpd[13904]: Server starting service.
Mar 18 11:27:38.365055 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal show | tail'.
Mar 18 11:27:38.916010 osdx dhcpd[13904]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Mar 18 11:27:39.916517 osdx dhcpd[13904]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Mar 18 11:27:39.948188 osdx dhcpd[13904]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Mar 18 11:27:39.948234 osdx dhcpd[13904]: 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
Mar 18 11:27:41.287088 osdx systemd-journald[1668]: Runtime Journal (/run/log/journal/72104842365c481ca7f4174cfa44e1fe) is 2.0M, max 15.3M, 13.2M free.
Mar 18 11:27:41.287895 osdx systemd-journald[1668]: Received client request to rotate journal, rotating.
Mar 18 11:27:41.287972 osdx systemd-journald[1668]: Vacuuming done, freed 0B of archived journals from /run/log/journal/72104842365c481ca7f4174cfa44e1fe.
Mar 18 11:27:41.301564 osdx OSDxCLI[6731]: 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
Mar 18 11:27:41.287088 osdx systemd-journald[1668]: Runtime Journal (/run/log/journal/72104842365c481ca7f4174cfa44e1fe) is 2.0M, max 15.3M, 13.2M free.
Mar 18 11:27:41.287895 osdx systemd-journald[1668]: Received client request to rotate journal, rotating.
Mar 18 11:27:41.287972 osdx systemd-journald[1668]: Vacuuming done, freed 0B of archived journals from /run/log/journal/72104842365c481ca7f4174cfa44e1fe.
Mar 18 11:27:41.301564 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal clear'.
Mar 18 11:27:41.391822 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal show | tail'.
Mar 18 11:27:41.494406 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal show | tail'.
Mar 18 11:27:42.024072 osdx dhcpd[13954]: 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)
Mar 18 11:27:43.088111 osdx dhcpd[13954]: 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  2025/03/18 11:27:46  2025/03/18 23:27:46  2025/03/18 11:27:46

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
Mar 18 11:27:55.417079 osdx cfgd[1456]: [6731]Completed change to active configuration
Mar 18 11:27:55.419229 osdx dhcpd[14263]: Wrote 0 leases to leases file.
Mar 18 11:27:55.458089 osdx OSDxCLI[6731]: User 'admin' committed the configuration.
Mar 18 11:27:55.483921 osdx OSDxCLI[6731]: User 'admin' left the configuration menu.
Mar 18 11:27:55.494566 osdx dhcpd[14263]: Server starting service.
Mar 18 11:27:55.646450 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal show | tail'.
Mar 18 11:27:55.814499 osdx dhcpd[14263]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Mar 18 11:27:56.815054 osdx dhcpd[14263]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Mar 18 11:27:56.854513 osdx dhcpd[14263]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Mar 18 11:27:56.854550 osdx dhcpd[14263]: 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
Mar 18 11:27:58.576133 osdx systemd-journald[1668]: Runtime Journal (/run/log/journal/72104842365c481ca7f4174cfa44e1fe) is 2.0M, max 15.3M, 13.3M free.
Mar 18 11:27:58.578418 osdx systemd-journald[1668]: Received client request to rotate journal, rotating.
Mar 18 11:27:58.578482 osdx systemd-journald[1668]: Vacuuming done, freed 0B of archived journals from /run/log/journal/72104842365c481ca7f4174cfa44e1fe.
Mar 18 11:27:58.589572 osdx OSDxCLI[6731]: 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
Mar 18 11:27:58.576133 osdx systemd-journald[1668]: Runtime Journal (/run/log/journal/72104842365c481ca7f4174cfa44e1fe) is 2.0M, max 15.3M, 13.3M free.
Mar 18 11:27:58.578418 osdx systemd-journald[1668]: Received client request to rotate journal, rotating.
Mar 18 11:27:58.578482 osdx systemd-journald[1668]: Vacuuming done, freed 0B of archived journals from /run/log/journal/72104842365c481ca7f4174cfa44e1fe.
Mar 18 11:27:58.589572 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal clear'.
Mar 18 11:27:58.675773 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal show | tail'.
Mar 18 11:27:58.777424 osdx OSDxCLI[6731]: User 'admin' executed a new command: 'system journal show | tail'.
Mar 18 11:27:58.938529 osdx dhcpd[14313]: 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)
Mar 18 11:27:59.978461 osdx dhcpd[14313]: 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  2025/03/18 11:28:03  2025/03/18 23:28:03  2025/03/18 11:28:03