Networking Fundamentals · lesson 11 of 17 · 10 min
DHCP and IP assignment DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and network configuration to devices when they join a network. Without DHCP, every device would need a manually configured static IP. DHCP DORA process D — Discover: client broadcasts “I need an IP address” to the network. O — Offer: DHCP server responds with an available IP address and lease terms. R — Request: client broadcasts “I accept this offer” (in case multiple servers responded). A — Acknowledge: server confirms the lease. Client configures its interface. DHCP lease An IP address is leased for a set time (e.g. 24 hours). The client renews before expiry. If the lease expires without renewal, the IP returns to the pool. DHCP security risks Rogue DHCP server: an attacker runs their own DHCP server and assigns themselves as the default gateway — a man-in-the-middle attack. Mitigated by DHCP snooping on managed switches. DHCP starvation: attacker requests all available IPs, exhausting the pool so legitimate devices cannot get addresses — a DoS attack.
DHCP concepts
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