What are the four DHCP steps, and which are broadcast?

Question

I know the DORA acronym but keep mixing up which messages are broadcast vs unicast, and who sends what. Can someone lay it out cleanly?

NetForge Team · Accepted Answer

**D**iscover — client broadcasts (it has no IP and knows no server: 0.0.0.0 → 255.255.255.255). **O**ffer — server proposes an address, lease, and options; typically sent broadcast too since the client can't receive normal unicast yet (some clients set flags for unicast delivery). **R**equest — client **broadcasts again**, naming which server's offer it accepts — the broadcast is deliberate, so any *other* servers that offered know they lost and can reclaim. **A**ck — server confirms; lease starts. The two exam-critical details: the whole exchange is broadcasts on the local segment, which is why a client on a different subnet than the server needs `ip helper-address` on its gateway (the relay converts to unicast toward the server); and renewal at T1 (50% of lease) is plain **unicast** to the known server — no DORA repeat.

What are the four DHCP steps, and which are broadcast?

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