udhcp Server/Client is an embedded DHCP client and server that can be compiled seperately (19k and 17k respectively), or as one combined binary (29k). The server stores its lease file periodically, or by a signal (for systems with flash memory) in terms of absolute time of lease expiration, or time remaining in a lease (for systems with no clocks). The client calls helper scripts to do the work of configuring the interfaces for more flexibility. udhcp has been included in BusyBox and is no longer maintained as a separate project.
