创建DDNS动态域名解析服务器

1、先创建一个用户myddns
#useradd myddns
2、生成密码
#dnssec-keygen -a HMAC-MD5 -b 128  -n USER myddns
在当前目录下生成了两个文件：
Kmyddns.+157+59363.key
Kmyddns.+157+59363.private
3、配置DNS
#vi /etc/named.conf
添加以下内容：
key myddns {
     algorithm  HMAC-MD5.SIG-ALG.REG.INT;
      secret xEGzMJVu7aT81lC5QRzIg==;
};
其中secrect后的内容是用vi打开Kmyddns.+157+59363.private后，拷贝里面的密码文件得来的！
4、配置DHCP
#vi /etc/dhcpd.conf
先将第二行前面的“#”去掉，再在subnet 上面添加下面一行内容：
ddns-updates on;
在option domain-name 后，改成DNS的域名，例如“sunman.com”
在option domain-name-servers 后，填写好DNS服务器的IP地址，例如：192.168.1.112
然后在里面添加下面几行内容：
key myddns {
     algorithm  HMAC-MD5.SIG-ALG.REG.INT;
      secret xEGzMJVu7aT81lC5QRzIg==;
}

zone sunman.com. {
        primary 192.168.1.2;
        key myddns;
}

zone 1.168.192.in-addr.arpa. {
       primary 192.168.1.2;
       key myddns;
}
保存退出！
5、开启DNS和DHCP服务器
#service named start
#service dhcpd start
6、通过下面的命令排错
#tail -n 20 /var/log/messages | grep named    (指定显示靠后的20行内容）
#tail /var/log/messages | grep dhcpd          （全部显示所有内容）
7、linux客户端通过dhclient命令动态获取到IP，这时在DNS服务器的/var/named/chroot/var/named/下会生成两个扩展名是.jnl的文件。
还有一点要注意，linux客户端还必须执行下面的工作
#cp /usr/share/doc/dhclient-3.0pl2/dhclient.conf.sample /etc/dhclient.conf
生成一个dhclient.conf配置文件
#vi /etc/dhclient.conf
修改第一行内容，将双引号里的内容删掉，添加上自己的主机名。
最后再执行dhclient命令来获取IP。

   /etc/named.conf文件内容：

options {
   directory "/var/named";
   listen-on ports 53 {
       127.0.0.1;
       192.168.1.112;
};

forward first;
forwarders {202.38.64.1;202.96.199.133;};

};

zone "." IN {
        type hint;
        file "named.ca";
};

zone "localhost" IN {
        type master;
        file "localhost.zone";
};

zone "0.0.127.in-addr.arpa" IN {
        type master;
        file "localhost.arpa";
};

key myddns {
     algorithm  HMAC-MD5.SIG-ALG.REG.INT;
      secret xEGzMJVu7aT81lC5QRzIg==;
};

zone "sunman.com" IN {
    type master;
     file "sunman.zone";
    allow-update { key myddns; };
};

zone "1.168.192.in-addr.arpa" IN {
    type master;
    file "sunman.arpa";
    allow-update { key myddns; };
};

key "rndc-key" {
algorithm hmac-md5;
        secret "pq18UO7rODLStf5XVdg17Q==";
};

  controls {
        inet 127.0.0.1 port 953
                allow { 127.0.0.1; } keys { "rndc-key"; };
};

  /etc/dhcpd.conf配置文件内容：

ddns-update-style interim;
#ignore client-updates;
ddns-updates on;
subnet 192.168.1.0 netmask 255.255.255.0 {
# --- default gateway
        option routers 192.168.1.1;
        option subnet-mask 255.255.255.0;
        option nis-domain "domain.org";
        option domain-name "sunman.com";
        option domain-name-servers 192.168.1.112;
        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 192.168.1.128 192.168.1.255;
        range 192.168.1.10 192.168.1.100;
        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;
}
}

key myddns {
     algorithm  HMAC-MD5.SIG-ALG.REG.INT;
      secret xEGzMJVu7aT81lC5QRzIg==;
}

zone sunman.com. {
        primary 192.168.1.2;
        key myddns;
}

zone 1.168.192.in-addr.arpa. {
       primary 192.168.1.2;
       key myddns;
}