isc-dhcp 選項82

我對正確的 isc-dhcp 配置有疑問。我想根據交換機埠向使用者租用 IP 地址。為此，我使用 DLink DES-3200 系列交換機。一切正常，但最近我決定將特定子網租給所有未知使用者，即未在 dhcpd.conf 文件中明確指定。這是一個配置範例：# 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，如果添加添加讓我們說：

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（我將其包含在 shared-network ‘clients’ 子句中，見上文），我的所有客戶端都開始從 172.20.111.0 範圍獲取 IP 地址，無論它們是否為其埠指定了一個類。

有沒有辦法讓 dhcpd 伺服器先查看類聲明然後查看子網？

在閱讀 man dhcpd.conf 並玩弄之後，我設法通過對我的 dhcpd.networks 文件進行以下修改來實現我的目標：

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
}

}

現在它按照我想要的方式工作，雖然我不確定它是否會很好地擴展。

您寫道，您在 dhcpd.conf 文件的末尾添加了新子網。您需要將其添加到shared-network，否則 dhcpd 不會將這些網路視為替代方案。

引用自：https://serverfault.com/questions/393547