In a plain vanilla DHCP system, a client sends a request for "something about network" to the LAN. If there is a DHCP server on the LAN, it will send "something" back to the client. In a very basic setup this "something" is:
In most situation the list above will cover all the needs.
--- to be continued ---
Filename: /etc/dhcp3/dhclient.conf
Filename: /etc/dhcp3/dhclient-script
Some wants to have an MTA (postfix,qmail,sendmail) on their own laptop. If they boot up on a network where there is a blocking for port 25, then they want relay the mail through a host. To do this they need to know which server will accept them for forwarding mail. .....
Filename: /etc/dhcp3/dhclient-exit-hooks.d/smtp_server
Filename: /etc/dhcp3/dhclient-exit-hooks.d/ip_address
Filename: /etc/dhcp3/dhclient-exit-hooks.d/log_servers
Filename: /etc/dhcp3/dhclient-exit-hooks.d/ntp_servers
Filename: /etc/dhcp/dhcpd.conf