linux_dhcp配置

一、修改dhcp服务器ip地址：
vi /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
IPADDR=192.168.1.100
NETMASK=255.255.255.0
BOOTPROTO=static
HWADDR=00:0C:29:AF:43:A6
ONBOOT=yes
TYPE=Ethernet

vi /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
IPADDR=192.168.2.100
NETMASK=255.255.255.0
BOOTPROTO=static
HWADDR=00:0C:29:AF:43:A7

service network restart  使修改的地址生效

二、挂载光盘并安装DHCP软件包或用yum install dhcp 安装
mount -t iso9660 /dev/cdrom /media/cdrom/
cd /media/cdrom/RedHat/RPMS/
rpm -ivh dhcp-3.0.1-59.EL4.i386.rpm

三、复制dhcpd配置文件的样本
cp /usr/share/doc/dhcp*/dhcpd.conf.sample /etc/dhcpd.conf

四、编辑配置文件
vi /etc/dhcpd.conf

ddns-update-style interim;
ignore client-updates;

subnet 192.168.0.0 netmask 255.255.255.0 {

# --- default gateway
        option routers                  192.168.0.1;
        option subnet-mask              255.255.255.0;

        option nis-domain               "domain.org";
        option domain-name              "domain.org";                            #域名
        option domain-name-servers      192.168.1.1;

        option time-offset              -18000; # Eastern Standard Time
#       option ntp-servers              192.168.1.1;
#       option netbios-name-servers     192.168.1.1;
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- you understand Netbios very well
#       option netbios-node-type 2;

        range dynamic-bootp 192.168.0.128 192.168.0.254;
        default-lease-time 21600;
        max-lease-time 43200;

        # we want the nameserver to appear at a fixed address
        host ns {
                next-server marvin.redhat.com;
                hardware ethernet 12:34:56:78:AB:CD;
                fixed-address 207.175.42.254;
        }
}

修改为

ddns-update-style interim;                                                 #dhcp服务器和dns服务器内部更新自动协商
ignore client-updates;

subnet 192.168.1.0 netmask 255.255.255.0 {                               

        option routers                  192.168.1.1;                       #网关
        option subnet-mask              255.255.255.0;                     #子网掩码

        option domain-name-servers      202.103.24.68,202.103.0.117;       #DNS服务器地址

        option time-offset              -18000; # Eastern Standard Time
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- you understand Netbios very well
#       option netbios-node-type 2;

        range dynamic-bootp 192.168.1.101 192.168.1.200;                   #地址池
        default-lease-time 21600;                                          #默认租约时间（秒）
        max-lease-time 43200;                #最大租约时间（秒）

        # we want the nameserver to appear at a fixed address
        host JTWD01-28 {
                next-server marvin.redhat.com;
                hardware ethernet 00:1E:90:17:CC:67;                       #根据主机网卡mac地址分配IP地址
                fixed-address 192.168.1.88;                                #分配的固定IP地址
        }
}
subnet 192.168.2.0 netmask 255.255.255.0 {

        option routers                  192.168.2.1;
        option subnet-mask              255.255.255.0;

        option domain-name-servers      202.103.24.68,202.103.0.117;

        option time-offset              -18000; # Eastern Standard Time
# --- Selects point-to-point node (default is hybrid). Don't change this unless
# -- you understand Netbios very well
#       option netbios-node-type 2;

        range dynamic-bootp 192.168.2.101 192.168.2.200;
        default-lease-time 21600;
        max-lease-time 43200;
}

五、应用不同的网络接口:
vi /etc/sysconfig/dhcpd
DHCPDARGS=eth0  // DHCPDARGS=eth1                      #仅在eth0上提供dhcp服务

六、开启dhcp服务：
service dhcpd start                                    #stop status restart

注：/var/lib/dhcpd/dhcpd.leases 中记录着DHCP服务器向DHCP客户机提供租用的每个IP地址的信息

七、DHCP中继代理
1）首先安装dhcpd服务（里面包含中继代理服务）
2）启用路由功能:
echo  "1"  > /proc/sys/net/ipv4/ip_forward
3）然后修改dhcrelay的配置文件：
vi  /etc/sysconfig/dhcrelay
加入以下内容：
INTERFACES="eth0 eth1"
DHCPSERVERS="192.168.1.2"
4）给dhcp服务器增加新网段的地址池
5）启动中继服务
service  dhcrelay  start
6）客户端测试