客戶端斷開連接時的 DHCPD 清潔租約

有沒有辦法在客戶端斷開連接後立即強制 ISC DHCPD 觸發過期或釋放靜態租賃？

我想在客戶端連接（“送出”DHCPD 事件）和斷開連接（“到期”或“釋放”DHCPD 事件）後立即觸發腳本。

雖然第一個像魅力一樣起作用，但後者永遠不會觸發。有什麼建議嗎？

編輯：一個配置片段（帶有測試腳本）：

subnet 192.168.1.0 netmask 255.255.255.0 {
 range 192.168.1.40 192.168.1.49;

 on commit {
   set ip = binary-to-ascii (10, 8, ".", leased-address);
  execute ("/usr/local/bin/dhcp-test", "commit", ip);
 }
 on release {
   set ip = binary-to-ascii (10, 8, ".", leased-address);
   execute ("/usr/local/bin/dhcp-test", "release", ip);
 }
 on expiry {
   set ip = binary-to-ascii (10, 8, ".", leased-address);
   execute ("/usr/local/bin/dhcp-test", "expiry", ip);
 }
}

如果我理解正確，要進行靜態租約，您的配置中有類似的內容：

host static-1 {
   hardware ethernet 00:01:02:03:04:05;
   fixed-address 192.168.1.40;
}

這將按您的預期工作，但永遠不會釋放此 IP 地址（客戶端是否發送 DHCPRELEASE 無關緊要） - 因為從 dhcpd 的角度來看，它是靜態 IP。

您必須創建一個動態 IP（同樣，從 dhcpd 的角度來看），所以 dhcpd 將跟踪它。你可以這樣做：

# First create pseudo class
class "static-ip" { match suffix(hardware, 6); }

# Here you will declare all MAC of your clients and make it a subclass of "static-ip"
# class "<UNIQ-CLASSNAME>" { match if suffix(hardware, 6) = <CLIENT-MAC-ADDRESS>; } subclass "static-ip" <CLIENT-MAC-ADDRESS>;
# Example
class "static-1" { match if suffix(hardware, 6) = 00:01:02:03:04:05; } subclass "static-ip" 00:01:02:03:04:05;

# Next allocate an address for every client (inside subnet declaration):

subnet 192.168.1.0 netmask 255.255.255.0 {
 on commit {
   set ip = binary-to-ascii (10, 8, ".", leased-address);
  execute ("/usr/local/bin/dhcp-test", "commit", ip);
 }
 on release {
   set ip = binary-to-ascii (10, 8, ".", leased-address);
   execute ("/usr/local/bin/dhcp-test", "release", ip);
 }
 on expiry {
   set ip = binary-to-ascii (10, 8, ".", leased-address);
   execute ("/usr/local/bin/dhcp-test", "expiry", ip);
 }

# pool { range <ip-addr>; allow members of "<UNIQ-CLASSNAME>"; }
  pool { range 192.168.1.40; allow members of "static-1"; }
# pool { range 192.168.1.41; allow members of "static-2"; }
#... so on
}

為了使您的配置更加靈活，您可以將 class-subclass 和 pool-range 聲明放入不同的文件中，並將它們包含在 main dhcpd.conf 中

#dhcpd.conf
authoritative;
min-lease-time ...;
... etc.

include "/path/to/classes.conf";
include "/path/to/subnet.conf";

如您所見，我們將每個客戶端放入其自己的類中，並將其子類化為“static-ip”類。這是為了以防您想擁有另一個沒有靜態 IP 分配的子網，例如：

subnet 192.168.2.0 netmask 255.255.255.0 {
range 192.168.2.10 192.168.2.100;
deny members of "static-ip";
}

然後，您必須拒絕具有靜態 IP 分配的客戶端才能從該子網獲取 IP（使用拒絕關鍵字）。

這樣您就可以獲得動態 IP（從 dhcpd 的角度來看），但實際上它永遠不會改變（從客戶端的角度來看）

引用自：https://serverfault.com/questions/562628