Isc-dhcp-client

/etc/dhcp/dhclient.conf

option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
	domain-name, domain-name-servers, domain-search, host-name,
	dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
	netbios-name-servers, netbios-scope, interface-mtu,
	rfc3442-classless-static-routes, ntp-servers;
timeout 300;

/etc/dhcp/dhclient-enter-hooks.d/action

#!/bin/bash
echo reason = $reason >> /tmp/dhclient.$$
echo interface = $interface >> /tmp/dhclient.$$
echo new_ip_address  = $new_ip_address  >> /tmp/dhclient.$$
echo old_ip_address  = $old_ip_address  >> /tmp/dhclient.$$
echo new_network_number  = $new_network_number  >> /tmp/dhclient.$$
echo new_subnet_mask = $new_subnet_mask >> /tmp/dhclient.$$
echo new_broadcast_address = $new_broadcast_address >> /tmp/dhclient.$$
echo old_routers = $old_routers >> /tmp/dhclient.$$
echo new_routers = $new_routers >> /tmp/dhclient.$$
echo new_domain_search = $new_domain_search >> /tmp/dhclient.$$
echo new_domain_name_servers = $new_domain_name_servers >> /tmp/dhclient.$