floppyfw is a router and simple firewall on one single floppy. It uses Linux basic firewall capabilities, and has a very simple packaging system. It is perfect for masquerading and securing networks on ADSL and cable lines, using both static IP, DHCP, and PPPoE, and provides a simple installation, which usually involves editing of only one file on the floppy.
CyaSSL is a C-language-based SSL library targeted for embedded and RTOS environments, primarily because of its small size and speed. CyaSSL supports the industry standards up to the current TLS 1.2 level, is up to 20 times smaller than OpenSSL, includes SSL client libraries and an SSL server implementation, includes an OpenSSL compatibility layer, and offers several progressive ciphers such as RABBIT and HC-128. Dual licensed under both the GPLv2 and standard commercial licensing, it caters to a wide range of projects.
Sanewall is a firewall builder for Linux that uses an elegant language abstracted to just the right level. This makes it powerful and easy to use, audit, and understand. It allows you to create very readable configurations even for complex stateful firewalls. Sanewall can be used for almost any purpose, including control of any number of internal/external/virtual interfaces, control of any combination of routed traffic, setting up DMZ routers and servers, all kinds of NAT, providing strong protection (flooding, spoofing, etc.), transparent caches, source MAC verification, blacklists, and whitelists. Newer versions abstract the differences between IPv4 and IPv6, allowing you to define a common set of rules for both, while permitting specific rules for each as you need. Sanewall is a fork of FireHOL and can make use of existing FireHOL configurations.
dhcpcd is an RFC2131 compliant DHCP client. It is fully featured and yet lightweight: the binary is 60k as reported by size(1) on Linux i386. It has support for duplicate address detection, IPv4LL, carrier detection, and a merged resolv.conf and ntp.conf for which other DHCP clients require third party tools.
bandwidthd tracks usage of TCP/IP network subnets and builds HTML files with graphs to display network utilization. Charts are built by individual IP to show their utilization over 2, 8, 45, and 400 day periods. It color codes HTTP, HTTPS, TCP,UDP, ICMP, VPN, and P2P traffic. Unlike MRTG, it tracks each individual IP address and subnets, not the status of any particular link. Static mode is fast and easy to set up and has few dependencies. Database mode supports filtering by subnet, multiple sensors, custom reports and intervals, and can process thousands of IPs efficiently. Network utilization can be logged in CDF or a backend database.
Balance is a simple but powerful generic TCP proxy with round-robin load balancing and failover mechanisms. Its behavior can be controlled at runtime using a simple command line syntax. Balance supports IPv6 on the listening side, which makes it a very useful tool for IPv6 migration of IPv4 only services and servers.
wrt54g-linux is a mini-distribution for the Linksys wrt54g 802.11b/g access point and router. It includes basic tools such as sh, syslog, telnetd, httpd (with cgi-bin support), vi, snort, mount, insmod, rmmod, top, grep, find, nfs modules, etc. The installation script runs in about 20 seconds and installs strictly to the RAM disk. If you mess anything up, simply reset the box. After installing the distribution you'll be able to telnet in, add Web pages, change iptable rules, change routing, configure snort, etc.