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

Discover — client broadcasts (it has no IP and knows no server: 0.0.0.0 → 255.255.255.255). Offer — 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). Request — 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. Ack — 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.