3.2 KiB
| obj | wiki | rfc |
|---|---|---|
| concept | https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol | https://datatracker.ietf.org/doc/html/rfc2131 |
Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used to automate the assignment of IP addresses and other network configuration parameters to devices on a network. DHCP simplifies the process of configuring devices on a network by providing a centralized mechanism for dynamic IP address allocation.
Key Components
1. DHCP Server
A DHCP server is a network device responsible for assigning IP addresses and other configuration parameters to DHCP clients. It maintains a pool of available IP addresses and leases them to clients on a temporary basis.
2. DHCP Client
A DHCP client is a device (computer, printer, etc.) that requests network configuration information from a DHCP server. The client typically sends a DHCP discover message to locate available DHCP servers on the network.
DHCP Process
- DHCP Discover: When a device is connected to a network, it broadcasts a DHCP discover message to identify available DHCP servers.
- DHCP Offer: DHCP servers respond with a DHCP offer message, providing the client with an IP address and other configuration parameters.
- DHCP Request: The client selects one of the offered IP addresses and sends a DHCP request message to the chosen server.
- DHCP Acknowledge: The selected DHCP server responds with a DHCP acknowledge message, confirming the allocation of the requested IP address and providing additional configuration details.
- IP Lease Period: The DHCP server assigns an IP address to the client for a specific lease period. The client must renew its lease before expiration to retain the IP address.
DHCP Configuration Parameters
DHCP servers can provide various configuration parameters, including:
- IP Address: The primary network identifier assigned to the device.
- Subnet Mask: Defines the network's subnetwork structure.
- Default Gateway: Specifies the router that connects the local network to other networks.
- Domain Name System (DNS) Servers: Identifies the servers responsible for translating domain names into IP addresses.
- Domain Name: Provides the domain name associated with the assigned IP address.
- Lease Duration: The period for which the IP address is allocated to the client.
DHCP Security Considerations
- Rogue DHCP Servers: Unauthorized DHCP servers can cause network disruptions. Implementing DHCP snooping can help mitigate this risk.
- IP Address Exhaustion: Regularly monitoring and managing the IP address pool prevents exhaustion and ensures efficient resource utilization.
- Man-in-the-Middle Attacks: Using DHCP secure protocols, such as DHCPv6 Secure Neighbour Discovery (SEND), helps protect against man-in-the-middle attacks.