Networking
Explainer
DHCP: How You Get an IP Automatically
Join campus Wi-Fi and you get an IP in seconds. Four messages make it happen.
Quick check · tap an answer to continue
Lesson notes
Key points
- DHCP, the Dynamic Host Configuration Protocol, automatically gives hosts an IP address, subnet mask, default gateway and DNS server.
- The exchange follows four steps remembered as DORA: Discover, Offer, Request, Acknowledge.
- Discover is broadcast because the new client has no IP yet, so it uses source 0.0.0.0 and destination 255.255.255.255.
- The address is a lease with an expiry time, and the client must renew it or the server can reassign it.
Definitions
- DHCP
- Application-layer protocol over UDP ports 67/68 that leases IP settings to hosts automatically
Takeaway: DHCP leases IP settings through Discover, Offer, Request, Acknowledge.
Quick check: Which DHCP message does the client send first?
- Offer
- Request
- Discover
DHCPDORABroadcastLease
Lessons like this, for your syllabus.
Short narrated study videos written for your course, level and exam. Free to start.
Get lessons for your own syllabus