centos 7 上配置dnsmasq 同时支持ipv4和ipv6的DHCP服务

dnsmasq版本： dnsmasq 从2.6*版本开始支持DHCPv6功能

参考：https://blog.youkuaiyun.com/qq_35550345/article/details/86628962

dhcpv6原理：https://blog.youkuaiyun.com/qq_38265137/article/details/80466734

ifcfg配置参数介绍：https://blog.youkuaiyun.com/chinaltx/article/details/86497165

一、不指定分配地址

• dnsmasq服务器

1. 配置dnsmasq服务器ipv6地址（本测试接口为eth0）
   /etc/sysconfig/network-scripts/ifcfg-eth0

   DEVICE=eth0
   TYPE=Ethernet
   
   ONBOOT=yes
   NM_CONTROLLED=no
   BOOTPROTO=dhcp
   DEFROUTE=yes
   IPV4_FAILURE_FATAL=yes
   
   PEERDNS=yes
   
   IPV6INIT=yes
   IPV6to4INIT=yes
   IPV6FORDING=yes
   IPV6ADDR=fd00::1/64

   /etc/sysconfig/network
    

   NETWORKING_IPV6=yes

    

2. 设置dnsmasq.conf 

   read-ethers
   log-dhcp
   log-queries
   log-facility=/var/log/dnsmasq.log
   addn-hosts = /var/lib/cobbler/cobbler_hosts
   domain=local
   dhcp-lease-max=1800
   server=/local/
   resolv-file=/etc/dnsmasq.upstream
   interface=eth0
   
   cache-size=1024
   
   # This is one of the key options. dnsmasq tries to move out servername
   # and PXE filename from special fields into DHCP options.
   # Some old clients can't understand those DHCP options, so they
   # will not be able to boot via PXE without this option enabled.
   # For example gPXE will not work while iPXE works fine.
   dhcp-no-override
   
   # for many simultaneously DHCPDISCOVVER requests dnsmasq can offer
   # the same IP for two differnt MAC addresses. This option prevents it
   # by assigning IPs one by one instead of using hash algorithm.
   dhcp-sequential-ip
   
   #ipv4
   dhcp-option=6,10.10.1.2
   dhcp-range=internal,10.10.1.128,10.10.1.254,255.255.255.0,120m
   dhcp-option=net:internal,option:router,10.10.1.2
   dhcp-boot=net:internal,pxelinux.0,boothost,10.10.1.2
   
   #ipv6
   dhcp-range=fd00::22, fd00::44, 64, 1h
   enable-ra
   #domain-needed
   #resolv-file=/etc/resolv.dnsmasq.conf
   

   检查语法并启动dnsmasq：dnsmasq -test

   杀掉测试进程后启动dnsmasq &
   
   dhcp租用信息：/var/lib/dnsmasq/dnsmasq.leases

• 客户端配置

1. 网卡配置
   客户机上的接口为eth0，网卡配置文件/etc/sysconfig/network-scripts/ifcfg-eth0

   DEVICE=eth0
   ONBOOT=yes
   #禁止NetworkManager管理网卡
   NM_CONTROLLED=no 
   HWADDR=
   #USERCTL=no
   PEERDNS=yes
   BOOTPROTO=dhcp #只能小写
   #BOOTPROTO=dhcp6  打开这个只会获取ipv6的地址
   DHCPV6C=yes
   IPV6INIT=yes

    

2. 网络配置文件/etc/sysconfig/network

   NETWORKING_IPV6=yes
   
   IPV6_AUTOCONF=yes  #yes表示自动获取地址

    

3. 测试：
   dhclient -6 -v eth0

二、指定分配地址

使用dnsmasq 有状态DHCPv6下发特定租约

上面的方式是dnsmasq按照特定算法给客户端分配ipv4和ipv6地址，如果想给每个客户端分配指定地址，需要增加以下配置。

1. dnsmasq服务器（dnsmasq.conf ）
   配置和上面一样，添加以下语句

   dhcp-host=id:00:03:01:00:08:00:27:5c:b9:f0, [fd00::22]

   修改配置需要重启dnsmasq服务

2. 客户端

   根据官方描述，dhclient版本为4.1+支持ipv6。为了支持DUID-LL要在/etc/dhcp/dhclient.conf中写入：

        ZQ send dhcp6.client-id = concat(00:03:00, hardware);
   /etc/sysconfig/network-scripts/ifcfg-eth0跟上面一样
   配置/etc/sysconfig/network

   NETWORKING_IPV6=yes
   
   IPV6_AUTOCONF=no  

   客户端租约文件/var/lib/dhclient/dhclient6.leases
    

三、问题分析

centos7使用NetworkManager启动dhclient （NM_CONTROLLED=yes ）

相关文件在/var/lib/NetworkManager/

查看dhcliemt进程       

ps aux | grep dhclient 

/sbin/dhclient -d -q -6 -N -sf /usr/libexec/nm-dhcp-helper -pf /var/run/dhclient6-eth0.pid -lf /var/lib/NetworkManager/dhclient6-5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03-eth0.lease -cf /var/lib/NetworkManager/dhclient6-eth0.conf eth0

红色部分为租约信息和配置文件路径。