A3Com is a set of Perl modules and utilites which use SNMP to manage 3Com switches, such as SS3900s, SS9300s, and CoreBuilders. Tools included will search/dump/store bridge tables, ARP tables, retrieve system info, save and restore configurations in batch mode, upload new software in batch mode, change passwords, reboot switches, dump VLAN configurations, and more.
Addns.pl is a self-contained DynDNS update client for DynDNS.org (and possibly others). It supports a variety of IP detection methods including external webcheck/router pages. It also supports multiple configurations and hostnames, smart abuse prevention, and custom/static/dynamic DNS, and can run as a daemon, commandline options only, or with a configuration file.
adsl.sh is a Bash script to easily manage an ADSL pptp connection (most French "France Telecom" ADSL equipment uses this). It's pre-configured for this kind of connection, but you can easily edit the script to make it suit your needs. It can also update your IP adress on dhs.org and/or dyndns.org, and gracefully restart Apache (if you use VirtualHosts, it's mandatory when IP changes).
Afghan Hound Quote of the Day Daemon uses both TCP and UDP port 17 to return a random quote from fortune(6) style quote files. It has performance benefits over other programs which use fortune(6) to source their quotes. The server also includes the ability to limit the number of client connections per second. Client and benchmarking programs are included in the package.
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.
Angel is a simple yet useful tool to monitor the services on your network. Technically speaking, it's a Perl program that runs every 'n' minutes (usually fired from your cron) and calls different perl subprograms (referred to as "plugins" from now on) to do the actual testing. It will then generate an HTML table containing the status of your network.
Angst is an active sniffer, based on libpcap and libnet. It dumps into a file the payload of all the TCP packets received on the specified ports. It implements two methods for active sniffing. Angst is able to monitor ARP requests, and after enabling IP forwarding on the local host, it sends ARP replies mapping all IPs to the local MAC address. Also, it can flood the local network with random MAC addresses (like macof), causing switches to send packets to all ports.
Anteater is a log analyser for MTA logfiles (such as those produced by sendmail and postfix). The tool is written in 100% C++ and is very easy to customize. Input, output, and the analysis are modular class objects with a clear interface. Currently, there are modules for reading the syslog format of sendmail and postfix that do up to eight useful analyses and write the result in plain ASCII or HTML, to stdout or to files.