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
Oct 10 08:20:59.368533 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Oct 10 08:20:59.446560 osdx systemd[1]: Started "DHCP Server Service instance main".
Oct 10 08:20:59.452141 osdx dhcpd[28813]: Wrote 0 leases to leases file.
Oct 10 08:20:59.452496 osdx cfgd[1328]: [24906]Completed change to active configuration
Oct 10 08:20:59.457332 osdx OSDxCLI[24906]: User 'admin' committed the configuration.
Oct 10 08:20:59.501166 osdx OSDxCLI[24906]: User 'admin' left the configuration menu.
Oct 10 08:20:59.596876 osdx dhcpd[28813]: Server starting service.
Oct 10 08:20:59.751038 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 10 08:20:59.875690 osdx dhcpd[28813]: DHCPDISCOVER from 10:00:00:00:00:02 via eth0
Oct 10 08:21:00.421639 osdx zebra[1281]: [RZ3YY-GPH41][EC 100663310] snmp[warning]: Warning: Failed to connect to the agentx master agent ([NIL]):

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 Thu 2024-10-10 08:21:01 UTC, end at Thu 2024-10-10 08:21:01 UTC. --
Oct 10 08:21:01.681384 osdx systemd-journald[1712]: Runtime journal (/run/log/journal/c2d6011d26b547ba87daa360869210a1) is 2.0M, max 16.0M, 14.0M free.
Oct 10 08:21:01.704365 osdx OSDxCLI[24906]: 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 Thu 2024-10-10 08:21:01 UTC, end at Thu 2024-10-10 08:21:01 UTC. --
Oct 10 08:21:01.681384 osdx systemd-journald[1712]: Runtime journal (/run/log/journal/c2d6011d26b547ba87daa360869210a1) is 2.0M, max 16.0M, 14.0M free.
Oct 10 08:21:01.704365 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal clear'.
Oct 10 08:21:01.797317 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 10 08:21:01.932825 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 10 08:21:01.991722 osdx dhcpd[28855]: 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  2024/10/10 08:21:05  2024/10/10 20:21:05  2024/10/10 08:21:05

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
Oct 10 08:21:14.791830 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Oct 10 08:21:14.853938 osdx systemd[1]: Started "DHCP Server Service instance VRF0".
Oct 10 08:21:14.856833 osdx cfgd[1328]: [24906]Completed change to active configuration
Oct 10 08:21:14.860332 osdx OSDxCLI[24906]: User 'admin' committed the configuration.
Oct 10 08:21:14.863720 osdx dhcpd[29147]: Wrote 0 leases to leases file.
Oct 10 08:21:14.888702 osdx OSDxCLI[24906]: User 'admin' left the configuration menu.
Oct 10 08:21:15.062886 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 10 08:21:15.416154 osdx dhcpd[29147]: Server starting service.
Oct 10 08:21:15.769790 osdx zebra[1281]: [RZ3YY-GPH41][EC 100663310] snmp[warning]: Warning: Failed to connect to the agentx master agent ([NIL]):
Oct 10 08:21:16.186868 osdx dhcpd[29147]: 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 Thu 2024-10-10 08:21:16 UTC, end at Thu 2024-10-10 08:21:16 UTC. --
Oct 10 08:21:16.977188 osdx systemd-journald[1712]: Runtime journal (/run/log/journal/c2d6011d26b547ba87daa360869210a1) is 2.0M, max 16.0M, 14.0M free.
Oct 10 08:21:16.998418 osdx OSDxCLI[24906]: 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 Thu 2024-10-10 08:21:16 UTC, end at Thu 2024-10-10 08:21:18 UTC. --
Oct 10 08:21:16.977188 osdx systemd-journald[1712]: Runtime journal (/run/log/journal/c2d6011d26b547ba87daa360869210a1) is 2.0M, max 16.0M, 14.0M free.
Oct 10 08:21:16.998418 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal clear'.
Oct 10 08:21:17.090350 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 10 08:21:17.193787 osdx OSDxCLI[24906]: User 'admin' executed a new command: 'system journal show | tail'.
Oct 10 08:21:17.432102 osdx dhcpd[29189]: Server starting service.
Oct 10 08:21:18.291912 osdx dhcpd[29189]: 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 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  2024/10/10 08:21:20  2024/10/10 20:21:20  2024/10/10 08:21:20