[[SOLVED] dhcpd поймать событие]

Нет, только если косвенно.

только парсить леасы, возможно по инотифу.
как вариант , заюзать наговские приблуды типа mysql и кидать по триггеру ( сейчас прям сам и придумал - не бейте )

ebuild   R   ] net-misc/dhcp-4.2.1  USE="doc ipv6 ssl vim-syntax -ldap (-selinux)" 0 k

cat /etc/dhcp/dhcpd.conf

... skip ...
on commit {
  set clientIP = binary-to-ascii(10, 8, ".", leased-address);
  set clientMAC = binary-to-ascii(16, 8, ":", substring(hardware, 1, 6));
  set reversdnsname = concat(binary-to-ascii(10, 8, ".", reverse (1, leased-address)),".in-addr.arpa.");
#   host-decl-name
#  execute("/etc/dhcp/publish-ip-mac.pl", "commit", clientIP, clientMAC);
  execute("/etc/dhcp/publish-ip-mac.pl", "commit", clientIP, host-decl-name);
}

on release {
  set clientIP = binary-to-ascii(10, 8, ".", leased-address);
  set clientMAC = binary-to-ascii(16, 8, ":", substring(hardware, 1, 6));
  execute("/etc/dhcp/publish-ip-mac.pl", "release", clientIP, clientMAC);
}

on expiry {
  set clientIP = binary-to-ascii(10, 8, ".", leased-address);
  if(exists agent.remote-id) {
    set clientMAC = binary-to-ascii(16, 8, ":", substring(option agent.remote-id, 2, 6));
    execute("/etc/dhcp/publish-ip-mac.pl", "expiry", clientIP, clientMAC);
  } else {
    execute("/etc/dhcp/publish-ip-mac.pl", "expiry", clientIP);
  }
}

... skip ...
cat /etc/dhcp/publish-ip-mac.pl

#!/usr/bin/perl

use strict;
use warnings;

my $type = shift;
my $ip = shift;
my $mac = shift;

my $leaseFile = "/var/log/dhcp-test.log";

if(not defined($mac))
{
    $mac="00:00:00:00:00:00";
}
# Fork so we can return control
# to the dhcp server ASAP.
my $pid = fork();

# If we're the child, do whatever we need to do
if($pid == 0) {
    open(FH, ">> $leaseFile");
    print FH "$type\t$ip\t$mac\n";
    close(FH);
}

ловится все, только release очень редко(не все посылают) =(