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Resolved Question

When to switch to Link Local Address

Jun 29, 2018 5:24PM PDT

If a networking embedded device that has no routable configuration but DHCP enabled and receives no response from any DHCP server in the network - should the device switch over to Link Local Addressing mode? IN such a case how is the DHCP request timeout is considered?

If not then when should a networking device gain a Link Local address?

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Such is usually covered in a class environment.
Jun 29, 2018 6:45PM PDT

But I did write router code in the 90s so the answers are wholly dependent on the device's programming. There are some standards but I found you can't rely on them. If I find a device bails out on DHCP we switch it to fixed IP addressing.

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Link Local Addressing
Jul 1, 2018 4:59AM PDT

Thanks - please confirm if "device bails out on DHCP" meant that device did not received a response / OFFER from any DHCP server within the network. Also generally what should be the timeout for such a scenario.

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Confirmed.
Jul 1, 2018 9:54AM PDT

I have found devices that just don't work on DHCP. This means it's confirmed.

As to your question on timeout, you would be reading the RFPs. I don't do that for others. Maybe someone else will. Here's your RFP for DHCP: https://www.ietf.org/rfc/rfc2131.txt