Redhat AS5U2配置DHCP服务器

  首先安装dhcp-3.0.5-7.el5.i386.rpm， 配置文件是/etc/dhcpd.conf，
租约数据库文件是/var/lib/dhcpd/dhcpd.leases，   [root@mailsvr1 ~]# vi /etc/dhcpd.conf    
里面没什么，
see /usr/share/doc/dhcp*/dhcpd.conf.sample 可以将这个文件覆盖现在的文件   [root@mailsvr1 ~]# cp /usr/share/doc/dhcp-3.0.5/dhcpd.conf.sample /etc/dhcpd.conf
cp：是否覆盖“/etc/dhcpd.conf”? y   /etc/dhcpd.conf文件的简单解释 ddns-update-style interim; #定义所支持的DNS动态更新类型
ignore client-updates;         #忽略客户端更新 subnet 192.168.0.0 netmask 255.255.255.0 { # --- default gateway
        option routers                  192.168.0.1;               #网关地址
        option subnet-mask              255.255.255.0;     #子网掩码：默认子网掩码         option nis-domain               "domain.org";
        option domain-name              "domain.org";   #DNS后缀
        option domain-name-servers      192.168.1.1;  #DNS服务器地址         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;   #动态IP地址范围
        default-lease-time 21600;                             #默认IP租约时间，单位秒
        max-lease-time 43200;             #客户端IP租约时间的最大值，单位秒         # 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;
        }
}
可以修改为 ddns-update-style interim;
ignore client-updates;
option domain-name "haha.com"; 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 192.168.2.1;
option domain-name "haha.com"; range dynamic-bootp 192.168.2.20 192.168.2.250;
default-lease-time 21600;
max-lease-time 43200;
}   启动服务；
/etc/init.d/dhcpd start   查看日志/var/log/messages，出现如下，表示服务成功启动。
Dec 23 19:57:33 mailsvr1 dhcpd: Internet Systems Consortium DHCP Server V3.0.5-RedHat
Dec 23 19:57:33 mailsvr1 dhcpd: Copyright 2004-2006 Internet Systems Consortium.
Dec 23 19:57:33 mailsvr1 dhcpd: All rights reserved.
Dec 23 19:57:33 mailsvr1 dhcpd: For info, please visit