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 28 07:24:45.473014 osdx OSDxCLI[10537]: User 'admin' committed the configuration.
Jul 28 07:24:45.516334 osdx dhcpd[12310]: Server starting service.
Jul 28 07:24:45.561542 osdx OSDxCLI[10537]: User 'admin' left the configuration menu.
Jul 28 07:24:45.899212 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 28 07:24:45.905857 osdx dhcpd[12310]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Jul 28 07:24:46.913728 osdx dhcpd[12310]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Jul 28 07:24:46.986807 osdx dhcpd[12310]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Jul 28 07:24:46.986849 osdx dhcpd[12310]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Jul 28 07:24:48.034616 osdx dhcpd[12310]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Jul 28 07:24:48.034647 osdx dhcpd[12310]: 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
Jul 28 07:24:49.271235 osdx systemd-journald[1773]: Runtime Journal (/run/log/journal/a46937b51a3a4c469575696f63c9d620) is 2.0M, max 15.3M, 13.2M free.
Jul 28 07:24:49.277989 osdx systemd-journald[1773]: Received client request to rotate journal, rotating.
Jul 28 07:24:49.278090 osdx systemd-journald[1773]: Vacuuming done, freed 0B of archived journals from /run/log/journal/a46937b51a3a4c469575696f63c9d620.
Jul 28 07:24:49.289528 osdx OSDxCLI[10537]: 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 28 07:24:49.271235 osdx systemd-journald[1773]: Runtime Journal (/run/log/journal/a46937b51a3a4c469575696f63c9d620) is 2.0M, max 15.3M, 13.2M free.
Jul 28 07:24:49.277989 osdx systemd-journald[1773]: Received client request to rotate journal, rotating.
Jul 28 07:24:49.278090 osdx systemd-journald[1773]: Vacuuming done, freed 0B of archived journals from /run/log/journal/a46937b51a3a4c469575696f63c9d620.
Jul 28 07:24:49.289528 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal clear'.
Jul 28 07:24:49.559404 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 28 07:24:49.790381 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 28 07:24:50.142571 osdx dhcpd[12366]: 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)
Jul 28 07:24:51.194844 osdx dhcpd[12366]: 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  2025/07/28 07:24:55  2025/07/28 19:24:55  2025/07/28 07:24:55

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 28 07:25:09.884457 osdx cfgd[1473]: [10537]Completed change to active configuration
Jul 28 07:25:09.884526 osdx dhcpd[12713]: Wrote 0 leases to leases file.
Jul 28 07:25:09.904455 osdx OSDxCLI[10537]: User 'admin' committed the configuration.
Jul 28 07:25:09.936651 osdx dhcpd[12713]: Server starting service.
Jul 28 07:25:09.955884 osdx OSDxCLI[10537]: User 'admin' left the configuration menu.
Jul 28 07:25:10.208560 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal show | tail'.
Jul 28 07:25:10.786093 osdx dhcpd[12713]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Jul 28 07:25:11.786922 osdx dhcpd[12713]: DHCPOFFER on 10.0.0.5 to 10:00:00:00:00:02 via eth0
Jul 28 07:25:11.834187 osdx dhcpd[12713]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Jul 28 07:25:11.834228 osdx dhcpd[12713]: 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
Jul 28 07:25:13.734037 osdx systemd-journald[1773]: Runtime Journal (/run/log/journal/a46937b51a3a4c469575696f63c9d620) is 2.0M, max 15.3M, 13.3M free.
Jul 28 07:25:13.737276 osdx systemd-journald[1773]: Received client request to rotate journal, rotating.
Jul 28 07:25:13.737372 osdx systemd-journald[1773]: Vacuuming done, freed 0B of archived journals from /run/log/journal/a46937b51a3a4c469575696f63c9d620.
Jul 28 07:25:13.793147 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal clear'.
Jul 28 07:25:13.934830 osdx dhcpd[12769]: 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 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 28 07:25:13.734037 osdx systemd-journald[1773]: Runtime Journal (/run/log/journal/a46937b51a3a4c469575696f63c9d620) is 2.0M, max 15.3M, 13.3M free.
Jul 28 07:25:13.737276 osdx systemd-journald[1773]: Received client request to rotate journal, rotating.
Jul 28 07:25:13.737372 osdx systemd-journald[1773]: Vacuuming done, freed 0B of archived journals from /run/log/journal/a46937b51a3a4c469575696f63c9d620.
Jul 28 07:25:13.793147 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal clear'.
Jul 28 07:25:13.934830 osdx dhcpd[12769]: 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)
Jul 28 07:25:14.000185 osdx OSDxCLI[10537]: User 'admin' executed a new command: 'system journal show | tail'.

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  2025/07/28 07:25:17  2025/07/28 19:25:17  2025/07/28 07:25:17