Dynamic Host Configuration Protocol for IPv4 (DHCPv4) server daemon.

The main driving force behind this was OpenBSD's Google Summer of Code 2014.

Tested on OpenBSD/amd64 and OpenBSD/sparc64 both directly and through a relay agent (HP A5800 Switch) with a variety of clients:

• Windows XP, 7, Phone
• dhcpcd 5.5.6 on Android
• dhcpcd 6.4.2 on Linux
• udhcpc 1.14.3 on Samsung TV
• udhcpc 1.11.2 on Ubiquiti airOS 5.5
• udhcpc 0.9.9 on Ubiquiti airOS 4.0
• OpenBSD dhclient
• Intel UNDI Boot Agent PXE-2.0, 2.1
• iPXE 1.0.0+ (09c5) inside QEMU 2.0.0
• Cisco IP Phone 7941 (requires DHCP option 150 to be faked)
• RouterBOOT on a big-endian MIPS board
• Xerox WorkCentre 3220
• dhcdrop http://www.netpatch.ru/devel/dhcdrop/
• sdhcp http://galos.no-ip.org/sdhcp
• Sony PlayStation 3
• Pioneer VSX-921K
• TP-link TL-WR841N
• TP-link TL-WR741N (makes 6 DHCPDISCOVERs before SELECTING)
• some Belkin router (without the backdoor) (gets a lease, then releases it, then re-discovers asking for the same one, all with xid 0x1)
• Sony Bravia TV (option 57 violates (RFC 2132); they probably wanted to write 9216 (0x2400) bytes and copied the length (0x02) byte on the left, which makes it look like 548 (0x0224) bytes, which of course is illegal)
• Linksys WRP400

• a proper configuration file parser (Grégoire Duchêne was working on that in another GSoC project) integrated into dhcpctl + the format documented
• maybe transaction support will be needed to keep the reload process sane
• re-check all cases when a dynamic range overlaps some static host entries
• Support other operating systems. I have working code for Windows + Linux but need to put it all together. My previous DHCP server manipulated ARP instead of sending stuff on BPF. Then it's valgrind time :-)
• DHCPv6 support. We need to understand the bloody RFC and support a small subset. Certainly no rush at any cost. RFC 4361 will be required as the identifiers seem to make sense between address families (and not just for tracking stolen laptops).
• Lease on-disk-dumper and multicast-syncer. I was sort of hoping it would be a separate process, but we'll see. Likely to happen after the parser.
• Some address-liveness awareness code, most likely ICMP before DHCPOFFERs. Maybe ARP snooping over dynamic ranges? Would require another 2MB bitmap.
• On commit/expiry/release is a cool feature in ISC DHCP 4.3. We could use such a mechanism to implement DDNS registration; command with environment variables containing lease information would do whatever you want it to.

Remember, it's a work in progress. Your minimal Debian installation will need:

$ apt-get install git libc6-dev libbsd-dev libevent-dev libpcap-dev gcc make pkg-config
$ git clone https://github.com/pelikan/dhcpd.git
$ cd dhcpd && ./configure
$ cd dhcpd && make
$ cd ../dhcpctl && make
$ useradd -r -d /var/empty dhcp
$ mkdir -p /var/empty

The development is mainly done on OpenBSD and Gentoo. Patches welcome, but please try to keep them small. No autotools!