Check-Mac-Address

These scenarios show how the feature check-mac-address works for 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 and see if there are warnings in your logs. Also, this test check the server’s behaviour in regular 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

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
May 22 09:10:18.011929 osdx OSDxCLI[29758]: User 'admin' added a new cfg line: 'set service dhcp-server shared-network dhcp subnet 10.0.0.0/24 start 10.0.0.5 stop 10.0.0.5'.
May 22 09:10:18.161896 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
May 22 09:10:18.226775 osdx systemd[1]: Started "DHCP Server Service instance main".
May 22 09:10:18.229642 osdx cfgd[1125]: [29758]Completed change to active configuration
May 22 09:10:18.232472 osdx dhcpd[32402]: Wrote 0 leases to leases file.
May 22 09:10:18.233591 osdx OSDxCLI[29758]: User 'admin' committed the configuration.
May 22 09:10:18.267882 osdx OSDxCLI[29758]: User 'admin' left the configuration menu.
May 22 09:10:18.350088 osdx dhcpd[32402]: Server starting service.
May 22 09:10:18.423198 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal show | tail'.
May 22 09:10:18.726538 osdx dhcpd[32402]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0

Step 3: Set the following configuration 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
-- Logs begin at Wed 2024-05-22 09:10:20 UTC, end at Wed 2024-05-22 09:10:20 UTC. --
May 22 09:10:20.208843 osdx systemd-journald[1514]: Runtime journal (/run/log/journal/99893f06e2ec475e9e852fdd13370208) is 2.0M, max 16.0M, 14.0M free.
May 22 09:10:20.235399 osdx OSDxCLI[29758]: 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
-- Logs begin at Wed 2024-05-22 09:10:20 UTC, end at Wed 2024-05-22 09:10:20 UTC. --
May 22 09:10:20.208843 osdx systemd-journald[1514]: Runtime journal (/run/log/journal/99893f06e2ec475e9e852fdd13370208) is 2.0M, max 16.0M, 14.0M free.
May 22 09:10:20.235399 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal clear'.
May 22 09:10:20.322010 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal show | tail'.
May 22 09:10:20.421661 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal show | tail'.
May 22 09:10:20.822683 osdx dhcpd[32444]: 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 eth0 mac 10:00:00:00:00:05

Step 8: Set the following configuration in DUT1:

set interfaces 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  2024/05/22 09:10:23  2024/05/22 21:10:23  2024/05/22 09:10:23

Test Check MAC Address VRF

Description

This scenario configures a DHCP server with VRF instead of regular interfaces and checks the option check-mac-address. To check this option you will need to send packets with differences in Source MAC for link layer and the client MAC from the application layer.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces eth0 address 10.0.0.1/24
set interfaces 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 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
May 22 09:10:31.599406 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
May 22 09:10:31.631409 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
May 22 09:10:31.681353 osdx systemd[1]: Started "DHCP Server Service instance VRF0".
May 22 09:10:31.684086 osdx cfgd[1125]: [29758]Completed change to active configuration
May 22 09:10:31.687652 osdx OSDxCLI[29758]: User 'admin' committed the configuration.
May 22 09:10:31.690635 osdx dhcpd[32730]: Wrote 0 leases to leases file.
May 22 09:10:31.754401 osdx OSDxCLI[29758]: User 'admin' left the configuration menu.
May 22 09:10:31.791727 osdx dhcpd[32730]: Server starting service.
May 22 09:10:31.918212 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal show | tail'.
May 22 09:10:32.144182 osdx dhcpd[32730]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0

Step 3: Set the following configuration 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
-- Logs begin at Wed 2024-05-22 09:10:33 UTC, end at Wed 2024-05-22 09:10:33 UTC. --
May 22 09:10:33.797811 osdx systemd-journald[1514]: Runtime journal (/run/log/journal/99893f06e2ec475e9e852fdd13370208) is 2.0M, max 16.0M, 14.0M free.
May 22 09:10:33.824607 osdx OSDxCLI[29758]: 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
-- Logs begin at Wed 2024-05-22 09:10:33 UTC, end at Wed 2024-05-22 09:10:34 UTC. --
May 22 09:10:33.797811 osdx systemd-journald[1514]: Runtime journal (/run/log/journal/99893f06e2ec475e9e852fdd13370208) is 2.0M, max 16.0M, 14.0M free.
May 22 09:10:33.824607 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal clear'.
May 22 09:10:33.910686 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal show | tail'.
May 22 09:10:34.013121 osdx OSDxCLI[29758]: User 'admin' executed a new command: 'system journal show | tail'.
May 22 09:10:34.219961 osdx dhcpd[304]: 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)
May 22 09:10:34.351061 osdx zebra[1078]: [RZ3YY-GPH41][EC 100663310] snmp[warning]: Warning: Failed to connect to the agentx master agent ([NIL]):

Step 7: Set the following configuration in DUT1:

set interfaces eth0 mac 10:00:00:00:00:05

Step 8: Set the following configuration in DUT1:

set interfaces 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  2024/05/22 09:10:37  2024/05/22 21:10:37  2024/05/22 09:10:37