isc-dhcp option82

Question

我有一个关于正确的isc-dhcp配置的问题。我想根据交换机端口将ip地址租赁给用户。为此，我使用DLink DES-3200系列交换机。一切运行良好，但最近我决定将特定的子网租给所有未知用户，即没有在dhcpd.conf文件中显式指定。下面是一个配置示例：# dhcpd.conf

default-lease-time 30;
max-lease-time 60;
authoritative;
log-facility local7;
option domain-name-servers 8.8.8.8;

include "/usr/local/etc/dhcpd/dhcpd.classes";

shared-network "clients"
{
    subnet 10.5.20.0 netmask 255.255.255.0 {}
    include "/usr/local/etc/dhcpd/dhcpd.networks";
}

dhcpd.classes

class "10.5.20.4_2" { match if ( substring(option agent.remote-id,2,15)="10.5.20.4" and binary-to-ascii(10, 16, "",  substring(option agent.circuit-id, 4, 2)) = "2" ); }
class "10.5.20.4_1" { match if ( substring(option agent.remote-id,2,15)="10.5.20.4" and binary-to-ascii(10, 16, "",  substring(option agent.circuit-id, 4, 2)) = "1" ); }
class "10.5.20.2_1" { match if ( substring(option agent.remote-id,2,15)="10.5.20.2" and     binary-to-ascii(10, 16, "",  substring(option agent.circuit-id, 4, 2)) = "1" ); }
class "10.5.20.2_3" { match if ( substring(option agent.remote-id,2,15)="10.5.20.2" and binary-to-ascii(10, 16, "",  substring(option agent.circuit-id, 4, 2)) = "3" ); }
class "10.5.20.2_2" { match if ( substring(option agent.remote-id,2,15)="10.5.20.2" and binary-to-ascii(10, 16, "",  substring(option agent.circuit-id, 4, 2)) = "2" ); }
class "10.5.20.2_4" { match if ( substring(option agent.remote-id,2,15)="10.5.20.2" and binary-to-ascii(10, 16, "",  substring(option agent.circuit-id, 4, 2)) = "4" ); }

dhcpd.networks

subnet 172.30.20.0 netmask 255.255.255.0
{
   option subnet-mask 255.255.255.0;
   option routers 172.30.20.1;
    pool {range 172.30.20.3; allow members of "10.5.20.4_2"; }
    pool {range 172.30.20.2; allow members of "10.5.20.4_1"; }
}
subnet 172.30.160.0 netmask 255.255.255.0
{
   option subnet-mask 255.255.255.0;
   option routers 172.30.160.1;
    pool {range 172.30.160.3; allow members of "10.5.20.2_1"; }
    pool {range 172.30.160.4; allow members of "10.5.20.2_3"; }
    pool {range 172.30.160.10; allow members of "10.5.20.2_2"; }
    pool {range 172.30.160.12; allow members of "10.5.20.2_4"; }
}

因此，如果添加add，比方说：

subnet 172.20.111.0  netmask 255.255.255.0 {
                        option routers 172.20.111.1;
                        max-lease-time 60;
                        min-lease-time 30;
                        range 172.20.111.10  172.20.111.20 ;
                        }

在dhcpd.networks文件的末尾(我将其包含在共享-网络‘客户端’子句中，请参见上文)，我的所有客户端都开始从172.20.111.0范围内获取ip地址，不管它们是否有为其端口指定的类。

是否有办法使dhcpd服务器首先查看类声明，然后查看子网？

Answer 1

在阅读man dhcpd.conf并四处游玩之后，我通过对我的dhcpd.networks文件进行以下修改，成功地实现了我的目标：

subnet 172.20.111.0  netmask 255.255.255.0 {
    pool {
        option routers 172.20.111.1;
        max-lease-time 60;
        min-lease-time 30;
        range 172.20.111.10  172.20.111.20 ;
        deny members of "10.5.20.4_1";
        deny members of "10.5.20.4_2";
        deny members of "10.5.20.2_1";
        #  .... etc
}

}

现在它的工作方式是我想要的，虽然我不确定它是否能很好地扩展。

Answer 2

您可以在dhcpd.conf文件的末尾添加新的子网。您需要将其添加到shared-network中，否则dhcpd将不会将这些网络视为替代方案。

Answer 3

只是对这个旧的但仍然有效的线程的一个补充。它简化了子网部分，但每个固定IP增加一行。

class "FastIP"{
      match pick-first-value (option agent.circuit-id);
}

同以前一样：

class "IP-10.1.2.3" {
       match if option agent.circuit-id = "YourOp82Value";
}

为每个Op82值添加以下内容，将固定IP客户从自由池中排除在外:子类"FixedIP“"YourOp82Value"；

在子网中：

deny members of "FixedIP";
pool { 
        allow members of "IP-10.1.2.3" ; 
        range 10.1.2.3 10.1.2.3;
}

这样，您就不必用大量的拒绝行拥挤子网部分。一个就行了。