All In One By Linux (openSUSE) | DHCP 服务器 (Server) 配置和使用(PXE+Pool+IP&MAC)

实践 | Practices 2024年10月23日

First | 序

最近想要记录一些 All In One By Linux 折腾历程

上篇介绍了 PPPOE & Basic route setup

🔽 🔽 🔽

这篇记录一下 DHCP 服务器的配置和使用过程

What is DHCP ? | 什么是 DHCP

DHCP服务器（Dynamic Host Configuration Protocol，动态主机配置协议服务器）是一个网络服务，它自动为设备（如计算机、手机、打印机等）分配网络参数，使这些设备能够在网络中通信。DHCP 服务器的主要功能是为设备提供以下信息：

IP地址：分配给每台设备的唯一地址，用于在网络中进行通信。
子网掩码：用于确定网络部分和主机部分的划分。
网关地址：设备与外部网络（如互联网）通信时的默认路由。
DNS服务器地址：用于将域名（如 www.example.com）解析为IP地址。

DHCP工作原理

DHCP 是一种客户端-服务器协议，主要通过以下过程进行工作：

发现（Discover）：当客户端（例如新连接到网络的电脑）启动时，它会发送一个广播请求，试图找到一个可用的 DHCP 服务器。
提供（Offer）：DHCP 服务器接收到客户端的请求后，会提供一个未分配的IP地址，以及其他相关的网络参数，并发送回客户端。
请求（Request）：客户端接收到 DHCP 服务器的响应后，选择其中一个 DHCP 提供的 IP 地址，并请求租用该地址。
确认（Ack）：DHCP 服务器确认了客户端的请求，并将 IP 地址分配给客户端，同时通知客户端该地址的租赁期（租期可能是几小时、几天等）。

DHCP的优势

自动化：不需要管理员手动为每台设备配置网络参数。
灵活性：设备在网络上移动时可以自动获取新的 IP 地址。
IP 地址管理：DHCP 服务器通过 IP 地址租赁机制来管理地址池，确保 IP 地址不会冲突或被浪费。

使用场景

家庭网络：路由器通常充当 DHCP 服务器，分配家中所有设备的 IP 地址。
企业网络：企业网络中的 DHCP 服务器为成百上千的设备分配和管理 IP 地址。
公共网络：如咖啡馆、机场等公共 Wi-Fi 网络中，DHCP 服务器用于分配临时 IP 地址。

通过 DHCP，网络管理员可以轻松地管理网络中的设备，并确保所有设备都有正确的网络配置。

以上释义来自ChatGPT

Version | 版本

OS | 系统

dhcp-server

Install | 安装

Linux 上最常用的 DHCP 服务器软件是 isc-dhcp-server

只需使用对应的包管理器安装isc-dhcp-server即可

Debian

sudo apt-get install isc-dhcp-server

CentOS

sudo dnf install dhcp-server

SUSE

sudo zypper install dhcp-server

Deploy | 配置

安装完成以后

需要配置DHCP服务器需要修改两个文件

/etc/dhcpd.conf
/etc/sysconfig/dhcpd

RPM 系配置文件路径如上不同的系统配置路径可能有差异

/etc/dhcpd.conf

▲ 是主要的配置文件

用于定义 DHCP 服务器如何分配 IP 地址和其他网络参数

/etc/sysconfig/dhcpd

▲ 这是一个系统配置文件

用于控制 DHCP 服务器的启动和运行包含

监听接口: 指定 DHCP 服务器监听的网络接口。
启动选项: 例如是否以调试模式启动、是否启用 IPv6 支持等。
用户和组: 指定 DHCP 服务器运行的用户和组

/etc/dhcpd.conf

首先来看 /etc/dhcpd.conf

▼ 以下是一个简单的 /etc/dhcpd.conf 示例

default-lease-time 43200;                                # 租约(使用)时间(秒)
      authoritative;                                     # 权威模式
      log-facility local7;                               # Log 配置
      max-lease-time 86400;                              # 租约时间上限
      option subnet-mask 255.255.255.0;                  # 子网掩码
      option broadcast-address 10.7.7.255;               # 广播地址
      option routers 10.7.7.7;                           # 网关地址
      option domain-name-servers 1.1.1.1;                # DNS 地址
      range 10.7.7.50  10.7.7.100;                       # 声明IP地址范围

配置完成后:

🔽 🔽 🔽

dhcp-server 将会以权威模式运行

从 10.7.7.50~10.7.7.100 随机选择一个IP地址分配给客户端 其中:

租约时间为43200
子网为255.255.255.0
网关为10.7.7.7
DNS地址为1.1.1.1
广播地址为10.7.7.255

/etc/sysconfig/dhcpd

随后编辑 /etc/sysconfig/dhcpd

上面说了此文件主要用于指定 dhcp 服务器监听的网卡接口完整文件如下所示

## Path:        Network/DHCP/DHCP server
## Description: DHCPv4 server settings
## Type:        string
## Default:     ""
## ServiceRestart: dhcpd
#
# Interface(s) for the DHCPv4 server to listen on.
#
# A special keyword is ANY, it will cause dhcpd to autodetect available
# interfaces.
#
# Examples: DHCPD_INTERFACE="eth0 eth1 eth2"
#           DHCPD_INTERFACE="ANY"
#
DHCPD_INTERFACE="p1p2"

## Path:        Network/DHCP/DHCP server
## Description: DHCPv6 server settings
## Type:        string
## Default:     ""
## ServiceRestart: dhcpd6
#
# Interface(s) for the DHCPv6 server to listen on.
#
# A special keyword is ANY, it will cause dhcpd to autodetect available
# interfaces.
#
# Examples: DHCPD6_INTERFACE="eth0 eth1 eth2"
#           DHCPD6_INTERFACE="ANY"
#
DHCPD6_INTERFACE="p1p2"

## Type:        list(yes,no,auto,)
## Default:
## Description: Restart dhcpv4 server when interface goes up (again)
#
# When the dhcp server is listening on a virtual interface, e.g. bridge,
# bonding or vlan, and this interface gets deleted and recreated during
# a network restart, dhcpd will stop answering requests on this interface
# and needs a restart as well.
# Begining with SLE-10 SP3, we install an if-up.d post script (see ifup(8)
# and also ifservices(5)), enabled in auto mode by default. This variable
# can be used to force or avoid the dhcp server restart:
#
#   no:   do not restart dhcpd
#  yes:   force a dhcp server restart
# auto:   (default) restart for virtual interfaces (bond,bridge,vlan) when
#         all interfaces used in DHCPD_INTERFACE variable are up as well.
#
# Except of this global setting, the variable can be specified per interface
# in the interface configurations (/etc/sysconfig/network/ifcfg-$name).
#
DHCPD_IFUP_RESTART="yes"

## Type:        list(yes,no,auto,)
## Default:
## Description: Restart dhcpv6 server when interface goes up (again)
#
# When the dhcp server is listening on a virtual interface, e.g. bridge,
# bonding or vlan, and this interface gets deleted and recreated during
# a network restart, dhcpd will stop answering requests on this interface
# and needs a restart as well.
# Begining with SLE-10 SP3, we install an if-up.d post script (see ifup(8)
# and also ifservices(5)), enabled in auto mode by default. This variable
# can be used to force or avoid the dhcp server restart:
#
#   no:   do not restart dhcpd
#  yes:   force a dhcp server restart
# auto:   (default) restart for virtual interfaces (bond,bridge,vlan) when
#         all interfaces used in DHCPD_INTERFACE variable are up as well.
#
# Except of this global setting, the variable can be specified per interface
# in the interface configurations (/etc/sysconfig/network/ifcfg-$name).
#
DHCPD6_IFUP_RESTART=""

## Type:        yesno
## Default:     yes
## ServiceRestart: dhcpd
#
# Shall the DHCP server dhcpd run in a chroot jail (/var/lib/dhcp)?
#
# Each time you start dhcpd with the init script, /etc/dhcpd.conf
# will be copied to /var/lib/dhcp/etc/.
#
# Some files that are important for hostname to IP address resolution
# (/etc/{gai.conf,nsswitch.conf,resolv.conf,host.conf,hosts,localtime},
# /lib/lib{resolv.so.*,libnss_*.so.*,libpthread.so.0,libdl.so.2}) will
# also be copied to the chroot jail by the init script when you start
# it (less than 1MB altogether).
#
# The pid file will be in /var/lib/dhcp/var/run/dhcpd.pid.
#
DHCPD_RUN_CHROOTED="yes"

## Type:        yesno
## Default:     yes
## ServiceRestart: dhcpd6
#
# Shall the DHCP server dhcpd run in a chroot jail (/var/lib/dhcp6)?
#
# Each time you start dhcpd with the init script, /etc/dhcpd6.conf
# will be copied to /var/lib/dhcp6/etc/.
#
# Some files that are important for hostname to IP address resolution
# (/etc/{gai.conf,nsswitch.conf,resolv.conf,host.conf,hosts,localtime},
# /lib/lib{resolv.so.*,libnss_*.so.*,libpthread.so.0,libdl.so.2}) will
# also be copied to the chroot jail by the init script when you start
# it (less than 1MB altogether).
#
# The pid file will be in /var/lib/dhcp6/var/run/dhcpd.pid.
#
DHCPD6_RUN_CHROOTED="yes"

## Type:        string
## Default:     "/etc/dhcpd.d"
## ServiceRestart: dhcpd
#
# Since version 3, dhcpd.conf can contain include statements.
# If you enter the names of any include files here, _all_ conf
# files will be copied to $chroot/etc/, when dhcpd is started in the
# chroot jail. (/etc/dhcpd.conf is always copied.)
#
# For your convenience, you can also specify entire directories,
# that will be copied inclusive subdirectories. The /etc/dhcpd.d
# directory will be copied by default when it exists.
#
# Example: "/etc/foo.bar.conf /etc/dhcpd.bootp-clients.conf"
#
DHCPD_CONF_INCLUDE_FILES="/etc/dhcpd.d"

## Type:        string
## Default:     "/etc/dhcpd.d"
## ServiceRestart: dhcpd6
#
# Since version 3, dhcpd.conf can contain include statements.
# If you enter the names of any include files here, _all_ conf
# files will be copied to $chroot/etc/, when dhcpd is started in
# the chroot jail. (/etc/dhcpd6.conf is always copied.)
#
# For your convenience, you can also specify entire directories,
# that will be copied inclusive subdirectories. The /etc/dhcpd6.d
# directory will be copied by default when it exists.
#
# Example: "/etc/foo.bar.conf /etc/dhcpd6.bootp-clients.conf"
#
DHCPD6_CONF_INCLUDE_FILES="/etc/dhcpd6.d"

## Type:        string
## Default:     "dhcpd"
## ServiceRestart: dhcpd
#
# Leave empty or enter "root" to let dhcpd run as root.
# Enter "dhcpd" to run dhcpd as user 'dhcpd'.
#
DHCPD_RUN_AS="dhcpd"

## Type:        string
## Default:     "dhcpd"
## ServiceRestart: dhcpd6
#
# Leave empty or enter "root" to let dhcpd run as root.
# Enter "dhcpd" to run dhcpd as user 'dhcpd'.
#
DHCPD6_RUN_AS="dhcpd"

## Type:        string
## Default:     ""
## ServiceRestart: dhcpd
#
# Other arguments that you want dhcpd to be started with
# (e.g. "-p 1234" for a non-standard port to listen on)
#
DHCPD_OTHER_ARGS=""

## Type:        string
## Default:     ""
## ServiceRestart: dhcpd6
#
# Other arguments that you want dhcpd to be started with
# (e.g. "-p 1234" for a non-standard port to listen on)
#
DHCPD6_OTHER_ARGS=""

🔽 主要看以下两项内容 🔽

DHCPD_INTERFACE="p1p2"
DHCPD6_INTERFACE="p1p2"

上述内容指定了 DHCP 服务器的监听网卡接口

即 DHCP(V4&V6) 均监听至 p1p2 提供服务

Start | 启动

配置完成后就可以启动 DHCP 服务器

systemctl enable --now dhcpd.service

确认DHCP 服务器正常运行

systemctl status dhcpd.service

🔽 回显如下 🔽

Use | 使用

启动完成以后我们需要验证DHCP服务器是否正常工作

也就是 DHCP 协议的工作流程

🔽 DHCP 服务器日志如下 🔽

Homelab-xzllll dhcpd: DHCPDISCOVER from 5e:9c:68:bf:97:48 (Pixel-6) via p1p2
Homelab-xzllll dhcpd: DHCPOFFER on 10.7.7.71 to 5e:9c:68:bf:97:48 (Pixel-6) via p1p2
Homelab-xzllll dhcpd: DHCPREQUEST for 10.7.7.71 (10.7.7.7) from 5e:9c:68:bf:97:48 (Pixel-6) via p1p2
Homelab-xzllll dhcpd: DHCPACK on 10.7.7.71 to 5e:9c:68:bf:97:48 (Pixel-6) via p1p2

🔼 可以看到DHCP服务器正常工作 🔼

Ex | 拓展

PXE

如果局域网中有 PXE 服务器

DHCP 服务需要为 PXE 客户端提供网络配置信息 (包括 PXE 服务器的地址和启动文件的位置) 从而引导PXE客户端启动

可以将 DHCP 服务器比作一个 "网络管理员"，它为 PXE 客户端（"新员工"）分配网络 "工位" (IP 地址) 和 "工作指南" (PXE 服务器地址和启动文件)。 PXE 客户端根据 "工作指南" 找到 "主管" (PXE 服务器) 并开始 "工作" (启动操作系统)

🔽 下方有更多PXE内容 🔽

🔽 PXE配置如下 🔽

      option space pxelinux;
      option pxelinux.magic code 208 = string;
      option pxelinux.configfile code 209 = text;
      option pxelinux.pathprefix code 210 = text;
      option pxelinux.reboottime code 211 = unsigned integer 32;
      option architecture-type code 93 = unsigned integer 16;
      
        class "pxeclients" {
        match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
        next-server 10.7.7.7;

                if option architecture-type = 00:07 {
                filename "iventoy_loader_16000_uefi";
                }
                else {
                filename "iventoy_loader_16000_bios";
                }
        }

🔽 组合(附DHCP基础)配置如下 🔽

Pool

DHCP 中有地址池的概念

可以根据不同的MAC地址来从不同的地址池中选取IP地址分配至客户端

当使用Podman创建容器时我希望DHCP能够分配给容器IP地址

但我不希望跟局域网中的客户端共用一个地址池

🔽 配置如下 🔽

subnet 10.7.7.0 netmask 255.255.255.0 {

        class "container--mac" {
        match if substring(hardware, 1, 3) = e6:b5:a0;
        }

        pool {
        allow members of "container--mac";
        range 10.7.7.101 10.7.7.150;
        }

        pool {
        deny members of "container--mac";
        range 10.7.7.50  10.7.7.100;
        }

      }

🔽 释义如下 🔽

class "container--mac" {
    match if substring(hardware, 1, 3) = e6:b5:a0;
}

class "container--mac"

▲ 定义了一个 DHCP 类，名称为 container--mac

match if substring(hardware, 1, 3) = e6:b5:a0

▲ 表示匹配那些硬件地址（MAC 地址）前 3 个字节为 e6:b5:a0 的设备

这意味着所有 MAC 地址以 e6:b5:a0 开头的客户端将被归类到 container--mac 类中。

pool {
    allow members of "container--mac";
    range 10.7.7.101 10.7.7.150;
}

这个 IP 地址池只允许属于 container--mac 类的客户端使用

即 MAC 地址以 e6:b5:a0 开头的客户端可以从 10.7.7.101 到 10.7.7.150 的地址范围中获取 IP 地址

allow members of "container--mac"

▲ 表示只有属于这个类的客户端才可以从该池中获取地址

pool {
    deny members of "container--mac";
    range 10.7.7.50  10.7.7.100;
}

这个 IP 地址池拒绝属于 container--mac 类的客户端使用

即 MAC 地址以 e6:b5:a0 开头的客户端不能从 10.7.7.50 到 10.7.7.100 的地址范围中获取 IP 地址

deny members of "container--mac"

▲ 表示属于 container--mac 类的客户端将被排除在该池之外

🔽 整体逻辑如下 🔽

如果客户端的 MAC 地址以 e6:b5:a0 开头

那么它会被分配到 10.7.7.101 到 10.7.7.150 的地址范围

如果客户端的 MAC 地址不以 e6:b5:a0 开头

它将从 10.7.7.50 到 10.7.7.100 的范围内分配 IP 地址

IP&MAC

更近一步来说

当使用Podman创建容器时我希望DHCP能够分配给容器指定的IP地址

做IP/MAC绑定

🔽 配置如下 🔽

subnet 10.7.7.0 netmask 255.255.255.0 {

        class "container--mac" {
        match if substring(hardware, 1, 3) = e6:b5:a0;
        }

        pool {
        allow members of "container--mac";
        range 10.7.7.101 10.7.7.150;
        }

        pool {
        deny members of "container--mac";
        range 10.7.7.50  10.7.7.100;
        }

      }
        host container01 {
        hardware ethernet e6:b5:a0:12:34:01;
        fixed-address 10.7.7.102;
        }

🔽 释义如下 🔽

这段配置的作用是为 MAC 地址为 e6:b5:a0:12:34:01 的设备（命名为 container01）分配一个固定的 IP 地址 10.7.7.102。不论何时该设备请求 IP，DHCP 服务器都会分配该固定地址，而不是从动态范围内随机分配

🔽 这里注意 host container01 的放置位置

DHCP + PXE + Pool + IP&MAC

恰好你跟我一样有上述所有的需求

这里我贴一下我的完整配置文件以防Copy时没注意格式

default-lease-time 43200;
      authoritative;
      log-facility local7;
      max-lease-time 86400;
      option subnet-mask 255.255.255.0;
      option broadcast-address 10.7.7.255;
      option routers 10.7.7.7;
      option domain-name-servers 1.1.1.1;
      option space pxelinux;
      option pxelinux.magic code 208 = string;
      option pxelinux.configfile code 209 = text;
      option pxelinux.pathprefix code 210 = text;
      option pxelinux.reboottime code 211 = unsigned integer 32;
      option architecture-type code 93 = unsigned integer 16;

      subnet 10.7.7.0 netmask 255.255.255.0 {

        class "pxeclients" {
        match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
        next-server 10.7.7.7;

                if option architecture-type = 00:07 {
                filename "iventoy_loader_16000_uefi";
                }
                else {
                filename "iventoy_loader_16000_bios";
                }
        }

        class "container--mac" {
        match if substring(hardware, 1, 3) = e6:b5:a0;
        }

        pool {
        allow members of "container--mac";
        range 10.7.7.101 10.7.7.150;
        }

        pool {
        deny members of "container--mac";
        range 10.7.7.50  10.7.7.100;
        }

      }

        host container01 {
        hardware ethernet e6:b5:a0:12:34:01;
        fixed-address 10.7.7.102;
        }

向你推荐

指南 | Guides

openSUSE MicroOS 安装 Cockpit 及配置虚拟化实践

4 个月前 • 阅读预计需要3分钟

工具 | Tools

bpftune - BPF driven auto-tuning | install & usage

5 个月前 • 阅读预计需要3分钟

实践 | Practices

eSIM Phone By USB Tethering To Landscape WAN 实践记录

7 个月前 • 阅读预计需要5分钟

openSUSE MicroOS 安装 Cockpit 及配置虚拟化实践

Intel® XL710-QDA1 with Lenovo ThinkCentre Tiny Compatibility Guide(兼容性指南)

Kured(KUbernetes REboot Daemon) with openSUSE MicroOS

bpftune - BPF driven auto-tuning | install & usage

All In One By Linux (openSUSE) | DHCP 服务器 (Server) 配置和使用(PXE+Pool+IP&MAC)

First | 序

What is DHCP ? | 什么是 DHCP

DHCP工作原理

DHCP的优势

使用场景

Version | 版本

OS | 系统

dhcp-server

Install | 安装

Debian

CentOS

SUSE

Deploy | 配置

/etc/dhcpd.conf

/etc/sysconfig/dhcpd

Start | 启动

Use | 使用

Ex | 拓展

PXE

Pool

IP&MAC

DHCP + PXE + Pool + IP&MAC

标签

xzllll

向你推荐

openSUSE MicroOS 安装 Cockpit 及配置虚拟化实践

bpftune - BPF driven auto-tuning | install & usage

eSIM Phone By USB Tethering To Landscape WAN 实践记录

openSUSE MicroOS 安装 Cockpit 及配置虚拟化实践

Intel® XL710-QDA1 with Lenovo ThinkCentre Tiny Compatibility Guide(兼容性指南)

Kured(KUbernetes REboot Daemon) with openSUSE MicroOS

bpftune - BPF driven auto-tuning | install & usage

First | 序

What is DHCP ? | 什么是 DHCP

DHCP工作原理

DHCP的优势

使用场景

Version | 版本

OS | 系统

dhcp-server

Install | 安装

Debian

CentOS

SUSE

Deploy | 配置

/etc/dhcpd.conf

/etc/sysconfig/dhcpd

Start | 启动

Use | 使用

Ex | 拓展

PXE

Pool

IP&MAC

DHCP + PXE + Pool + IP&MAC

标签

订阅我们的新内容

xzllll

向你推荐

openSUSE MicroOS 安装 Cockpit 及配置虚拟化实践

bpftune - BPF driven auto-tuning | install & usage

eSIM Phone By USB Tethering To Landscape WAN 实践记录