.. _example_service_dhcp-client_timeout:

#######
Timeout
#######

Test suite to validate DHCP client timeout and retry behavior.

The ISC DHCP client has specific timeout and retry behavior:
- Sends DHCPDISCOVER with exponential backoff (10s → 20s → 40s → 120s)
- Times out after 60 seconds if no DHCPOFFER received
- Retries after 30 seconds (OSDx configuration)
- Loops indefinitely until server responds

This test suite verifies:
- Client properly times out when no server is available
- Client recovers when server becomes available
- Fallback IP is applied when configured and DHCP fails

Note: These tests are intentionally slow due to DHCP timeout values.

**********************************
Test Client Timeout Without Server
**********************************

Description
===========

This scenario verifies that the DHCP client properly handles
the case when no DHCP server is available on the network.

Expected behavior:
- Client sends DHCPDISCOVER packets
- Client times out after ~60 seconds
- Client does NOT obtain an IP address
- Client continues retrying (loop)

Note: This test waits 70 seconds to ensure timeout occurs.

Scenario
========

.. include:: timeout/testclienttimeoutwithoutserver

.. raw:: html

  <hr>

****************************************
Test Client Recovery After Server Starts
****************************************

Description
===========

This scenario verifies that the DHCP client successfully
obtains an IP address when the server becomes available
after the client has already started requesting.

Expected behavior:
- Client starts without server, times out
- Server is started during client retry phase
- Client successfully obtains IP from server

Note: This test waits for initial timeout then starts server.

Scenario
========

.. include:: timeout/testclientrecoveryafterserverstarts

.. raw:: html

  <hr>

*******************************
Test Client Retry After Timeout
*******************************

Description
===========

This scenario verifies that the DHCP client continues
to retry after timeout, demonstrating the infinite retry loop.

Expected behavior:
- Client times out at 60s
- Client retries after 30s (OSDx retry interval)
- Second retry cycle begins

We verify by capturing DHCP traffic during retry phase.

Scenario
========

.. include:: timeout/testclientretryaftertimeout

.. raw:: html

  <hr>

***********************************
Test Fallback IP Applied On Timeout
***********************************

Description
===========

This scenario verifies that when a fallback IP is configured
and DHCP times out, the fallback IP is applied to the interface.

This is a single-DUT test (DUT0 only) - no server is needed.

Configuration:
- set interfaces ethernet eth0 address dhcp
- set interfaces ethernet eth0 dhcp client fallback 10.96.0.99/24

Expected behavior:
- Client sends DHCPDISCOVER
- No server responds, timeout occurs
- Fallback IP (10.96.0.99/24) is applied

Note: This tests the fallback mechanism on initial timeout.

Scenario
========

.. include:: timeout/testfallbackipappliedontimeout

.. raw:: html

  <hr>