Alt+Connect manages dialup connections, allowing a group of networked machines to share a single Internet connection through their server. Custom client software lets users to start or stop their internet connection, and the server (connectd) ensures that the connection remains up only while someone's using it. Features include support for multiple ISPs and links (modems or ISDN channels), connection control lists, ability to record the time a user spends online and charge him for it, and the ability to enable and disable IP forwarding as a machine starts or stops using the Internet.
AMaViS (A Mail Virus Scanner) scans e-mail attachments for viruses using third-party virus scanners available for UNIX environments. It resides on a UNIX (Linux) machine and looks through the attached files arriving via e-mail, generates reports when a virus is found and sets the delivery on hold.
Aps is a small tool for analyzing network traffic. It prints out a great deal of information about the relevant protocols including TCP, UDP, ARP, and ICMP. It allows you to filter IP addresses, hardware addresses, ports, and specific protocols. It comes with a little GTK-GUI displaying packet counters for each protocol.
Astaro Portscan Detection is a netfilter target which will attempt to detect TCP and UDP port scans and log them to syslog. This target is based upon Solar Designer's scanlogd. It suppports mutliple levels of logging, custom prefixes for entries, weighted total port scan detection, and port scan temporal spread detection.
CIPE (Crypto IP Encapsulation) is an ongoing project to build encrypting IP routers. The protocol used is as lightweight as possible. It is designed for passing encrypted packets between prearranged routers in the form of UDP packets. This is not as flexible as IPSEC but it is enough for the original intended purpose: securely connecting subnets over an insecure transit network.
Coyote Linux is a mini distribution designed for setting up network utility services such as Internet connection sharing, firewalling, or wireless access points. The goal is to make it as quick and easy as possible to set up a Linux system with only a minimal amount of Linux knowledge.
Dante is a free implementation of the proxy protocols SOCKS version 4 and SOCKS version 5 (RFC 1928). It can be used as a firewall between networks, controlling outgoing traffic. The package consists of two parts: a socks server and a proxy client that supports socks, HTTP proxies, and UPnP. RFC 1961 (GSSAPI) is supported in both the client and the server. Commercial support is available.