Fallback

Test suite to validate DHCP client IP fallback functionality.

When DHCP fails to obtain an IP address, the client can be configured with a fallback static IP address that will be used temporarily until DHCP becomes available again.

This test suite verifies that: - Fallback IP is applied when DHCP server is unreachable - Fallback IP is removed when DHCP succeeds - Fallback works with VRF - Fallback works with VLAN interfaces

Test DHCP Fallback to Static IP

Description

This scenario checks that when DHCP server is unavailable, the client applies the configured fallback IP address. This ensures the interface has connectivity even without DHCP. This is a single-DUT test (DUT0 only) - no server needed.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address dhcp
set interfaces ethernet eth0 dhcp client fallback 10.95.0.99/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Run command interfaces ethernet eth0 show at DUT0 and expect this output:

Test DHCP Fallback with VRF

Description

This scenario checks that DHCP fallback works correctly when the interface is in a VRF (Virtual Routing and Forwarding) context. This is a single-DUT test (DUT0 only) - no server needed.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address dhcp
set interfaces ethernet eth0 dhcp client fallback 10.95.0.99/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Run command interfaces ethernet eth0 show at DUT0 and expect this output:

Test DHCP Fallback with VLAN

Description

This scenario checks that DHCP fallback works correctly on VLAN sub-interfaces (VIF). This is a single-DUT test (DUT0 only) - no server needed.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 vif 100 address dhcp
set interfaces ethernet eth0 vif 100 dhcp client fallback 10.95.0.99/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Run command interfaces ethernet eth0 vif 100 show at DUT0 and expect this output:

Test DHCP No Fallback When Server Available

Description

This scenario checks that fallback IP is NOT applied when DHCP server is available from the beginning. We verify that DHCP IP is obtained successfully. NOTE: There may be a race condition where fallback briefly appears before DHCP completes - this test focuses on DHCP success.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address 10.95.0.1/24
set service dhcp-server shared-network dhcp subnet 10.95.0.0/24 start 10.95.0.5 stop 10.95.0.5
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 2: Set the following configuration in DUT1 :

set interfaces ethernet eth0 address dhcp
set interfaces ethernet eth0 dhcp client fallback 10.95.0.99/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Run command interfaces ethernet eth0 show at DUT1 and check if output contains the following tokens:

10.95.0.5