Hotplug lets you plug in new devices and use them immediately. That means that users won't need to learn so much system administration, since the Linux system will at least partially autoconfigure itself. Initially, hotplug included support for USB and PCI (Cardbus) devices, and could automatically configure some common network interfaces. Updated versions include IEEE 1394 (Firewire/i.Link) support and can download firmware to USB devices that need it.
Netplug is a Linux daemon that manages network interfaces in response to network cables being plugged in and out. If you're familiar with Windows XP, which just does the Right Thing when you plug an ethernet cable into a laptop, netplug will need no further explanation. Basically, netplug brings up an interface and runs a DHCP client when a cable is plugged into that interface, and it brings the interface down when the cable is unplugged. On a typical Linux system or laptop, you have to run a command (such as "/sbin/ifup") manually to handle these events, but netplug automates this for you.
DOCSIS Server is a DHCP/TFTP/TOD/syslog server that uses MySQL as a backend. If you have a DOCSIS Cable Modem headend, you can use this server to boot up cable modems and assign IP addresses to customer premise equipment. With a little bit of tweaking you could also use it as just a DHCP server attached to a MySQL database. It was designed to boot up more than 150 modems per second.
Firewall is a set of scripts (firewall, fwup, and fwdown) that implement an ipchains firewall and various forms of network address and port translation. All you have to do is read the policy file and edit it to reflect your topology and filtering policy. It supports many different types of network topology (single host, traditional forwarding, masquerading, port forwarding, alias port forwarding and NAT), up to 10 untrusted interfaces each with their own policy, and over 50 network applications. It also supports centralised administration of multiple remote firewalls (meta-firewall).
TFTP Server is a multi-threaded TFTP server, allowing any number of clients to connect simultaneously. It supports tsize, blksize, and interval options, PXE boot, and can be run standalone or as a daemon. Port ranges can be specified to work across firewalls. There is also a single port version, for situations where additional ports cannot be opened.