What does DHCP stand for?
DHCP stands for Dynamic Host Configuration Protocol. The protocol that automatically assigns IP addresses and network settings to devices. A rogue DHCP server can redirect traffic; DHCP snooping on switches blocks it.
DHCP hands out IP configuration automatically: address, subnet mask, default gateway, DNS servers and a lease time. The exchange has four steps, discover, offer, request and acknowledge, sent over UDP ports 67 (server) and 68 (client). A Windows client that receives no answer gives itself an address in 169.254.0.0/16, which is a quick sign that DHCP failed.
DHCP in practice: an example
A laptop joins the office network and broadcasts a discover message. The server offers 10.0.20.57, the laptop requests it and the server acknowledges with a lease of eight hours. When half the lease has passed the laptop asks to renew it and keeps the same address.
What DHCP is confused with
DHCP vs DNS: what is the difference?
DHCP assigns addresses and tells the client where the DNS server is. DNS resolves names to addresses. What DNS stands for
DHCP vs static addressing: what is the difference?
A static address is typed in by an administrator and never changes. A DHCP reservation gives the same result while keeping management in one place.
Which exams cover DHCP?
DHCP is on the official CompTIA acronym list for three of the four exams covered here.
- Security+ SY0-801: on the acronym list, not tied to one objective.
- Network+ N10-009: 1.0 (Networking Concepts); 3.0 (Network Operations); 4.0 (Network Security).
- A+ 220-1201 and 220-1202: 220-1201 2.0 (Networking).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. A workstation shows the address 169.254.18.4 and cannot reach anything. What does that indicate?
- It could not contact a DHCP server
- DNS is misconfigured
- The default gateway is down
- The address is a public IP
Show the answer
A. It could not contact a DHCP server. 169.254.0.0/16 addresses are self-assigned when no DHCP answer arrives. The fault is between the client and the DHCP service.
2. An attacker plugs in a device that answers DHCP requests with itself as the default gateway. Which switch feature blocks this?
- DHCP snooping
- Port mirroring
- Jumbo frames
- Spanning tree
Show the answer
A. DHCP snooping. DHCP snooping lets server replies through only on trusted ports, so a rogue server on an access port is ignored.
Sources: RFC 2131: Dynamic Host Configuration Protocol; NIST glossary: Dynamic Host Configuration Protocol. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.