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网站首页 ∷ 所有新闻 ∷ 行业资讯 ∷ ​Centos7.8部署DHCP及地址保留、超级作用域-北京赛维博信科技发展有限公司
​Centos7.8部署DHCP及地址保留、超级作用域-北京赛维博信科技发展有限公司
来源: | 作者:svbx001 | 发布时间: 2022-04-15 | 3364 次浏览 | 分享到:

一.准备工作

项目名称基础信息
操作系统Centos7.8
IP地址192.168.250.219
SElinux已关闭
防火墙已启用，开放相关端口：UDP/67和UDP/68
DHCP地址池192.168.250.2-192.168.250.90

二.部署DHCP服务器

1.yum方式安装dhcp服务
[root@dhcp-server ~]# yum -y install dhcp已加载插件：fastestmirror, langpacksLoading mirror speeds from cached hostfile
2.查看dhcpd.conf默认配置文件的内容

默认情况下，dhcpd.conf配置文件在 /etc/dhcp/目录下，默认的配置内容为空，如下：

[root@dhcp-server ~]# cd /etc/dhcp[root@dhcp-server dhcp]# ll总用量 8drwxr-xr-x. 2 root root   236月  102021 dhclient.ddrwxr-xr-x. 2 root root   284月  1216:09 dhclient-exit-hooks.d-rw-r--r--. 1 root root  1206月  102021 dhcpd6.conf-rw-r--r--. 1 root root  1176月  102021 dhcpd.confdrwxr-x---. 2 root dhcpd  284月  1216:09 scripts[root@dhcp-server dhcp]# cat dhcpd.conf## DHCP Server Configuration file.#   see /usr/share/doc/dhcp*/dhcpd.conf.example#   see dhcpd.conf(5) man page#[root@dhcp-server dhcp]#
3.复制example文件

从 /usr/share/doc/dhcp-*/dhcpd.conf.example复制文件到 /etc/dhcp下，文件名为 dhcpd.conf，进行覆盖。

[root@dhcp-server dhcp]# cp -a /usr/share/doc/dhcp*/dhcpd.conf.example /etc/dhcp/dhcpd.confcp：是否覆盖"/etc/dhcp/dhcpd.conf"？y[root@dhcp-server dhcp]#
4.查看example的配置信息
  1. [root@dhcp-server dhcp]# cat dhcpd.conf
  2. # dhcpd.conf
  3. #
  4. # Sample configuration file for ISC dhcpd
  5. #

  7. # option definitions common to all supported networks...
  8. option domain-name "example.org";
  9. option domain-name-servers ns1.example.org, ns2.example.org;

  11. default-lease-time 600;
  12. max-lease-time 7200;

  14. # Use this to enble / disable dynamic dns updates globally.
  15. #ddns-update-style none;

  17. # If this DHCP server is the official DHCP server for the local
  18. # network, the authoritative directive should be uncommented.
  19. #authoritative;

  21. # Use this to send dhcp log messages to a different log file (you also
  22. # have to hack syslog.conf to complete the redirection).
  23. log-facility local7;

  25. # No service will be given on this subnet, but declaring it helps the
  26. # DHCP server to understand the network topology.

  28. subnet 10.152.187.0 netmask 255.255.255.0{
  29. }

  31. # This is a very basic subnet declaration.

  33. subnet 10.254.239.0 netmask 255.255.255.224{
  34.   range 10.254.239.1010.254.239.20;
  35.   option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;
  36. }

  38. # This declaration allows BOOTP clients to get dynamic addresses,
  39. # which we don't really recommend.

  41. subnet 10.254.239.32 netmask 255.255.255.224{
  42.   range dynamic-bootp 10.254.239.4010.254.239.60;
  43.   option broadcast-address 10.254.239.31;
  44.   option routers rtr-239-32-1.example.org;
  45. }

  47. # A slightly different configuration for an internal subnet.
  48. subnet 10.5.5.0 netmask 255.255.255.224{
  49.   range 10.5.5.2610.5.5.30;
  50.   option domain-name-servers ns1.internal.example.org;
  51.   option domain-name "internal.example.org";
  52.   option routers 10.5.5.1;
  53.   option broadcast-address 10.5.5.31;
  54. default-lease-time 600;
  55.   max-lease-time 7200;
  56. }

  58. # Hosts which require special configuration options can be listed in
  59. # host statements.   If no address is specified, the address will be
  60. # allocated dynamically (if possible), but the host-specific information
  61. # will still come from the host declaration.

  63. host passacaglia {
  64.   hardware ethernet 0:0:c0:5d:bd:95;
  65.   filename "vmunix.passacaglia";
  66.   server-name "toccata.fugue.com";
  67. }

  69. # Fixed IP addresses can also be specified for hosts.   These addresses
  70. # should not also be listed as being available for dynamic assignment.
  71. # Hosts for which fixed IP addresses have been specified can boot using
  72. # BOOTP or DHCP.   Hosts for which no fixed address is specified can only
  73. # be booted with DHCP, unless there is an address range on the subnet
  74. # to which a BOOTP client is connected which has the dynamic-bootp flag
  75. # set.
  76. host fantasia {
  77.   hardware ethernet 08:00:07:26:c0:a5;
  78. fixed-address fantasia.fugue.com;
  79. }

  81. # You can declare a class of clients and then do address allocation
  82. # based on that.   The example below shows a case where all clients
  83. # in a certain class get addresses on the 10.17.224/24 subnet, and all
  84. # other clients get addresses on the 10.0.29/24 subnet.

  86. class"foo"{
  87.   match if substring (option vendor-class-identifier, 0, 4) = "SUNW";
  88. }

  90. shared-network 224-29{
  91.   subnet 10.17.224.0 netmask 255.255.255.0{
  92.     option routers rtr-224.example.org;
  93. }
  94.   subnet 10.0.29.0 netmask 255.255.255.0{
  95.     option routers rtr-29.example.org;
  96. }
  97.   pool {
  98.     allow members of "foo";
  99.     range 10.17.224.1010.17.224.250;
  100. }
  101.   pool {
  102.     deny members of "foo";
  103.     range 10.0.29.1010.0.29.230;
  104. }
  105. }
  106. [root@dhcp-server dhcp]#
5.修改dhcpd.conf配置文件

这里只配一个基本的网络DHCP服务，地址范围为规划的地址：[192.168.250.2,192.168.250.90]。

配置如下：

  1. [root@dhcp-server dhcp]# vim dhcpd.conf
  2. [root@dhcp-server dhcp]#

  4. # This is a very basic subnet declaration.

  6. subnet 192.168.250.0 netmask 255.255.255.0{
  7.   range 192.168.250.2192.168.250.90;  #指定IP地址范围
  8.   option routers 192.168.250.1;   #指定网关地址
  9.   option broadcast-address 192.168.250.255;  #指定广播地址
  10. default-lease-time 600;  #指定默认租约
  11.   max-lease-time 7200;  #指定最大租约
  12. }
6.重启DHCP服务测试
[root@dhcp-server dhcp]# systemctl restart dhcpd[root@dhcp-server dhcp]# systemctl status dhcpd● dhcpd.service - DHCPv4ServerDaemonLoaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled; vendor preset: disabled)Active: active (running) since 五 2022-04-1512:42:03 CST; 10s agoDocs: man:dhcpd(8)           man:dhcpd.conf(5)Main PID: 18776(dhcpd)Status: "Dispatching packets..."Tasks: 1CGroup: /system.slice/dhcpd.service└─18776/usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid

启动一个客户面，查看能否获得IP。

本次在LINUX客户机下，先配置自动获取IP地址

[root@mysvn ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0TYPE=EthernetBOOTPROTO=dhcp  #自动获取IP地址DEFROUTE=yesIPV4_FAILURE_FATAL=noNAME=eth0UUID=434372f7-39e5-48b7-968b-61dc7193c902DEVICE=eth0ONBOOT=yes

然后重启网络服务，查看获取的IP地址为 192.168.250.2/24，如下：

[root@mydhcpclient ~]# ip a1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN groupdefault qlen 1000    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever    inet6 ::1/128 scope host       valid_lft forever preferred_lft forever2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP groupdefault qlen 1000    link/ether 52:54:00:43:f4:24 brd ff:ff:ff:ff:ff:ff    inet 192.168.250.2/24 brd 192.168.250.255 scope global noprefixroute dynamic eth0       valid_lft 572sec preferred_lft 572sec    inet6 fe80::652b:6da4:4354:b80a/64 scope link tentative noprefixroute dadfailed       valid_lft forever preferred_lft forever    inet6 fe80::c1d:8fe4:757a:da37/64 scope link tentative noprefixroute dadfailed       valid_lft forever preferred_lft forever    inet6 fe80::941:8a6:6c27:1098/64 scope link tentative noprefixroute dadfailed       valid_lft forever preferred_lft forever3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN groupdefault qlen 1000    link/ether 52:54:00:d7:57:29 brd ff:ff:ff:ff:ff:ff    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0       valid_lft forever preferred_lft forever4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN groupdefault qlen 1000    link/ether 52:54:00:d7:57:29 brd ff:ff:ff:ff:ff:ff[root@mydhcpclient ~]#

三.配置保留地址

那么为什么要有保留地址呢？一些主机需要固定的IP，但是仍然使用DHCP来分配地址，配置完地址保留后，以后每次给这个主机分配的IP都是相同的。

还是打开配置文件 /etc/dhcp/dhcpd.conf

找到下面这部分：

# Fixed IP addresses can also be specified for hosts.   These addresses# should not also be listed as being available for dynamic assignment.# Hosts for which fixed IP addresses have been specified can boot using# BOOTP or DHCP.   Hosts for which no fixed address is specified can only# be booted with DHCP, unless there is an address range on the subnet# to which a BOOTP client is connected which has the dynamic-bootp flag# set.host fantasia {  hardware ethernet 08:00:07:26:c0:a5;fixed-address fantasia.fugue.com;}

然后进行修改，比如，这次要保留地址 192.168.250.10的地址为NC服务器，这台NC服务器的MAC地址为 08-3a-38-9d-9A-71，则进行如下配置：

host fantasia {  hardware ethernet 08:3a:38:9d:9A:71;  #被指定的主机的MAC地址fixed-address 192.168.250.10;    #指定的IP}

四.超级作用域

为什么要用到超级作用域，现在局域网用的是C类网段分配主机，但是主机数目大于254，一个C类网段不够分，所以要两个网段才行，还要这两个网段之间能够通信。这时候我们就可以把路由器和DHCP服务器结合到一起来用。

1.复制当前网卡副本
  1. [root@dhcp-server dhcp]# cd /etc/sysconfig/network-scripts/

  3. [root@dhcp-server network-scripts]# cp ifcfg-eth0 ifcfg-eth0:0
  4. [root@dhcp-server network-scripts]# vim ifcfg-eth0:0
  5. [root@dhcp-server network-scripts]#
  6. [root@dhcp-server network-scripts]# cat ifcfg-eth0:0
  7. TYPE=Ethernet
  8. PROXY_METHOD=none
  9. BROWSER_ONLY=no
  10. BOOTPROTO=none
  11. DEFROUTE=yes
  12. IPV4_FAILURE_FATAL=no
  13. NAME=eth0
  14. UUID=434372f7-39e5-48b7-968b-61dc7193c902
  15. DEVICE=eth0
  16. ONBOOT=yes
  17. IPADDR=192.168.251.219
  18. PREFIX=24
  19. GATEWAY=192.168.251.1
  20. DNS1=192.168.251.219
  21. [root@dhcp-server network-scripts]#

配置另一个的IP为 192.168.251.219。

2.修改DHCP的配置文件

/etc/dhcp/dhcpd.conf，找到下面部分：

shared-network 224-29{  subnet 10.17.224.0 netmask 255.255.255.0{    option routers rtr-224.example.org;}  subnet 10.0.29.0 netmask 255.255.255.0{    option routers rtr-29.example.org;}  pool {    allow members of "foo";    range 10.17.224.1010.17.224.250;}  pool {    deny members of "foo";    range 10.0.29.1010.0.29.230;}}[root@dhcp-server dhcp]#

进行修改：

shared-network 250-251{  subnet 192.168.250.0 netmask 255.255.255.0{    option routers 192.168.250.1;    range 192.168.250.2192.168.250.254;}  subnet 192.168.251.0 netmask 255.255.255.0{    option routers 192.168.251.1;    range 192.168.251.2192.168.251.200;}


 

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