Nmap is a powerful tool for discovering hosts on a network and enumerating what service they are offering. This can be used to find vulnerable systems, to locate rogue services on your network or simply for a first step in troubleshooting.

KeePass is a free/open-source password manager or safe which helps you to manage your passwords in a secure way. You can put all your passwords in one database, which is locked with one master key or a key-disk. So you only have to remember one single master password or insert the key-disk to unlock the whole database. The databases are encrypted using the best and most secure encryption algorithms currently known (AES and Twofish).

PWman is a text-based application for securely storing and managing passwords, based on the ui design of abook addressbook. PWman works on Linux, and should also run on most other UNIXes(untested).