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
Dec 03 12:45:43.561182 osdx OSDxCLI[2688]: User 'admin' added a new cfg line: 'show working'.
Dec 03 12:45:43.682653 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Dec 03 12:45:43.819175 osdx systemd[1]: Started dhcpd@main.service - "DHCP Server Service instance main".
Dec 03 12:45:43.821805 osdx cfgd[1634]: [2688]Completed change to active configuration
Dec 03 12:45:43.822457 osdx dhcpd[4484]: Wrote 0 leases to leases file.
Dec 03 12:45:43.846836 osdx dhcpd[4484]: Server starting service.
Dec 03 12:45:43.853046 osdx OSDxCLI[2688]: User 'admin' committed the configuration.
Dec 03 12:45:43.879914 osdx OSDxCLI[2688]: User 'admin' left the configuration menu.
Dec 03 12:45:44.035425 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal show | tail'.
Dec 03 12:45:44.180388 osdx dhcpd[4484]: 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
Dec 03 12:45:45.879357 osdx systemd-journald[1835]: Runtime Journal (/run/log/journal/d3b584433ca54f4e84c38003c593de3f) is 2.0M, max 15.3M, 13.3M free.
Dec 03 12:45:45.882661 osdx systemd-journald[1835]: Received client request to rotate journal, rotating.
Dec 03 12:45:45.882729 osdx systemd-journald[1835]: Vacuuming done, freed 0B of archived journals from /run/log/journal/d3b584433ca54f4e84c38003c593de3f.
Dec 03 12:45:45.890677 osdx OSDxCLI[2688]: 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
Dec 03 12:45:45.879357 osdx systemd-journald[1835]: Runtime Journal (/run/log/journal/d3b584433ca54f4e84c38003c593de3f) is 2.0M, max 15.3M, 13.3M free.
Dec 03 12:45:45.882661 osdx systemd-journald[1835]: Received client request to rotate journal, rotating.
Dec 03 12:45:45.882729 osdx systemd-journald[1835]: Vacuuming done, freed 0B of archived journals from /run/log/journal/d3b584433ca54f4e84c38003c593de3f.
Dec 03 12:45:45.890677 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal clear'.
Dec 03 12:45:45.994637 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal show | tail'.
Dec 03 12:45:46.120548 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal show | tail'.
Dec 03 12:45:46.288086 osdx dhcpd[4533]: 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  2024/12/03 12:45:49  2024/12/04 00:45:49  2024/12/03 12:45:49

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
Dec 03 12:45:55.803801 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Dec 03 12:45:55.875788 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Dec 03 12:45:55.968077 osdx systemd[1]: Started dhcpd@VRF0.service - "DHCP Server Service instance VRF0".
Dec 03 12:45:55.970804 osdx cfgd[1634]: [2688]Completed change to active configuration
Dec 03 12:45:55.971158 osdx dhcpd[4829]: Wrote 0 leases to leases file.
Dec 03 12:45:55.998598 osdx OSDxCLI[2688]: User 'admin' committed the configuration.
Dec 03 12:45:56.015787 osdx OSDxCLI[2688]: User 'admin' left the configuration menu.
Dec 03 12:45:56.035943 osdx dhcpd[4829]: Server starting service.
Dec 03 12:45:56.157957 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal show | tail'.
Dec 03 12:45:56.513613 osdx dhcpd[4829]: 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
Dec 03 12:45:57.970814 osdx systemd-journald[1835]: Runtime Journal (/run/log/journal/d3b584433ca54f4e84c38003c593de3f) is 2.0M, max 15.3M, 13.3M free.
Dec 03 12:45:57.971781 osdx systemd-journald[1835]: Received client request to rotate journal, rotating.
Dec 03 12:45:57.971826 osdx systemd-journald[1835]: Vacuuming done, freed 0B of archived journals from /run/log/journal/d3b584433ca54f4e84c38003c593de3f.
Dec 03 12:45:57.981901 osdx OSDxCLI[2688]: 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
Dec 03 12:45:57.970814 osdx systemd-journald[1835]: Runtime Journal (/run/log/journal/d3b584433ca54f4e84c38003c593de3f) is 2.0M, max 15.3M, 13.3M free.
Dec 03 12:45:57.971781 osdx systemd-journald[1835]: Received client request to rotate journal, rotating.
Dec 03 12:45:57.971826 osdx systemd-journald[1835]: Vacuuming done, freed 0B of archived journals from /run/log/journal/d3b584433ca54f4e84c38003c593de3f.
Dec 03 12:45:57.981901 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal clear'.
Dec 03 12:45:58.044041 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal show | tail'.
Dec 03 12:45:58.147079 osdx OSDxCLI[2688]: User 'admin' executed a new command: 'system journal show | tail'.
Dec 03 12:45:58.617676 osdx dhcpd[4878]: 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  2024/12/03 12:46:01  2024/12/04 00:46:01  2024/12/03 12:46:01