Domtools is a set of Unix shell commands that allow you to traverse DNS domain hierarchies, list all hosts (or subdomains) within a given domain, convert a host name to an IP address and vice-versa, convert a normal IP address to "in-addr.arpa." format and vice-versa, and more. These commands can be used manually, or included as building blocks for higher level DNS tools. Output is easily computer parsable.
ds3, short for dialup service 3, is a modem sharing server for Linux/UNIX. It allows no direct access to the modem/ISDN-adapter. Instead it provides a text based interface which can be accessed via telnet or by a client. Currently a java client, a gtk based client and a small gnome applet are available. Features of ds3 include user authentification and scripts or programs may be lauched through events created by users or triggered by an interval.