isc-dhcp-server：dhcp动态更新dns记录

Question

当 DHCP 提供地址时，我尝试动态更新 DNS 记录。但即使我在 /etc/bind/named.conf.local 中使用密钥指定了 allow-update，并在 /etc/dhcp/dhcpd.conf 中指定了相同的密钥，访问仍被拒绝并且超时。我还尝试在 allow update 中设置一个 ip 地址，但这似乎也不起作用。是不是我忘记在这里添加什么了？

尾部-f / var / log / syslog

 client 127.0.0.1#53398: update 'dirks.crtn/IN' denied due to allow-query
    dhcpd: unable to add forward map from sysadmin.dirks.crtn. to 192.168.56.102: timed out
    dhcpd: DHCPREQUEST for 192.168.56.102 from 08:00:27:25:73:69 (sysadmin) via eth1
    dhcpd: DHCPACK on 192.168.56.102 to 08:00:27:25:73:69 (sysadmin) via eth1

（/etc/dhcp/dhcpd.conf）中的配置

ddns-updates on;
ddns-update-style interim;
update-static-leases on;
authoritative;

key "update-key" {
algorithm hmac-md5;
secret "un7T4dJk6yjR6NS5xZql8w==";
};

allow unknown-clients;
use-host-decl-names on;
default-lease-time 1814400; #21 days
max-lease-time 1814400; #21 days
log-facility local7;


zone dirks.crtn. {
primary localhost;
key update-key;
}

zone 56.168.192.in-addr.arpa. {
primary localhost;
key update-key;
}

subnet 192.168.56.0 netmask 255.255.255.0 {
range 192.168.56.3 192.168.56.255;
option subnet-mask 255.255.255.0;
option domain-name-servers 192.168.56.2;
option domain-name "dirks.crtn";
ddns-domainname "dirks.crtn.";
ddns-rev-domainname "in-addr.arpa.";
}

/etc/bind/named.conf.local

key "update-key" {
algorithm hmac-md5;
secret "un7T4dJk6yjR6NS5xZql8w==";
};

zone "dirks.crtn" {
type master;
file "/etc/bind/dirks.crtn.db";
allow-update { key update-key; };
};

zone "56.168.192.in-addr.arpa {
type master;
file "/etc/bind/rev.56.168.192.in-addr.arpa";
allow-update { key update-key; };
};

我很感激任何答案:)