2.4 DHCP协议
2.4.1 简介
DHCP(Dynamic Host Configuration Protocol, 动态主机配置协议) 是一个用于局域网的网络协议，位于OSI模型的应用层，使用UDP协议工作，主要用于自动分配IP地址给用户，方便管理员进行统一管理。
DHCP服务器端使用 67/UDP，客户端使用68/UDP。DHCP运行分为四个基本过程，分别为请求IP租约、提供IP租约、选择IP租约和确认IP租约。客户端在获得了一个IP地址以后，就可以发送一个ARP请求来避免由于DHCP服务器地址池重叠而引发的IP冲突。
2.4.2 DHCP 报文格式
| op (1) | htype (1) | hlen (1) | hops (1) |
| xid (4) | |||
| secs (2) | flags (2) | ||
| ciaddr (4) | |||
| yiaddr (4) | |||
| siaddr (4) | |||
| giaddr (4) | |||
| chaddr (16) | |||
| sname (64) | |||
| file (128) | |||
| options (veriable) | |||
2.4.3 参考链接
2.4.3.1 RFC
- RFC 2131 Dynamic Host Configuration Protocol
- RFC 2132 DHCP Options and BOOTP Vendor Extensions
- RFC 3046 DHCP Relay Agent Information Option
- RFC 3397 Dynamic Host Configuration Protocol (DHCP) Domain Search Option
- RFC 3442 Classless Static Route Option for Dynamic Host Configuration Protocol (DHCP) version 4
- RFC 3942 Reclassifying Dynamic Host Configuration Protocol Version Four (DHCPv4) Options
- RFC 4242 Information Refresh Time Option for Dynamic Host Configuration Protocol for IPv6
- RFC 4361 Node-specific Client Identifiers for Dynamic Host Configuration Protocol Version Four (DHCPv4)
- RFC 4436 Detecting Netowrk Attachment in IPv4 (DNAv4)
