搭建DHCP服务，实现自动分配地址

[root@jhr-hub ~]# yum -y install dhcp




[root@jhr-hub ~]# cat /etc/dhcp/dhcpd
dhcpd6.conf  dhcpd.conf   
[root@jhr-hub ~]# cat /etc/dhcp/dhcpd.conf 
#
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp*/dhcpd.conf.example
#   see dhcpd.conf(5) man page
#
[root@jhr-hub ~]# 




[root@jhr-hub ~]# cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf
cp: overwrite ‘/etc/dhcp/dhcpd.conf’? y
[root@jhr-hub ~]#
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[root@jhr-hub ~]# vim /etc/dhcp/dhcpd.conf
[root@jhr-hub ~]# 
[root@jhr-hub ~]# 
[root@jhr-hub ~]# 
[root@jhr-hub ~]# cat /etc/dhcp/dhcpd.conf
# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#


# option definitions common to all supported networks...
option domain-name "example.org";
option domain-name-servers 3.7.191.1;


#设置当前的IP地址有效期，单位s
default-lease-time 60; 


#设置申请最大有效期
max-lease-time 60; 






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


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


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


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


#声明IP地址段和子网掩码


subnet 192.168.1.0 netmask 255.255.255.0 {
    #地址池：设置一个地址段
   range 192.168.1.100 192.168.1.200;
   #指定网关
   option routers 3.7.191.1;
   #获取DNS         
   option domain-name-servers 192.168.1.1; 
}


# This is a very basic subnet declaration.


subnet 10.254.239.0 netmask 255.255.255.224 {
  range 10.254.239.10 10.254.239.20;
  option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;
}


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


subnet 10.254.239.32 netmask 255.255.255.224 {
  range dynamic-bootp 10.254.239.40 10.254.239.60;
  option broadcast-address 10.254.239.31;
  option routers rtr-239-32-1.example.org;
}


# A slightly different configuration for an internal subnet.
subnet 10.5.5.0 netmask 255.255.255.224 {
  range 10.5.5.26 10.5.5.30;
  option domain-name-servers ns1.internal.example.org;
  option domain-name "internal.example.org";
  option routers 10.5.5.1;
  option broadcast-address 10.5.5.31;
  default-lease-time 600;
  max-lease-time 7200;
}


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


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


# 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;
}


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


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


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 10.17.224.10 10.17.224.250;
  }
  pool {
    deny members of "foo";
    range 10.0.29.10 10.0.29.230;
  }
}
[root@jhr-hub ~]#
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[root@jhr-hub ~]# systemctl start dhcpd
[root@jhr-hub ~]# systemctl status dhcpd
● dhcpd.service - DHCPv4 Server Daemon
   Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; disabled; vendor preset: disabled)
   Active: active (running) since Thu 2021-12-09 11:25:37 CST; 2s ago
     Docs: man:dhcpd(8)
           man:dhcpd.conf(5)
 Main PID: 142669 (dhcpd)
   Status: "Dispatching packets..."
   Memory: 5.0M
   CGroup: /system.slice/dhcpd.service
           └─142669 /usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid
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