Ident2 is an alternative approach to auth/ident services. It was written from the ground up and can run either as a child handler of inetd or as a standalone daemon with no user intervention. Users can set their own replies or toggle random replies, all at the system administrator's preference, of course. Full compliance with RFC1413 is attempted.
integrit is an alternative to file integrity verification programs like tripwire and aide. It helps you determine whether an intruder has modified a computer system. integrit's major advantages are a small memory footprint and simplicity. It works by creating a database that is a snapshot of the most essential parts of your computer system. You put the database somewhere safe, and you can then use it to make sure that no one has made any illicit modifications to the computer system. In the case of a break in, you know exactly which files have been modified, added, or removed.
iplog is a TCP/IP traffic logger. Currently, it is capable of logging TCP, UDP, and ICMP traffic. iplog is able to detect TCP port scans, TCP null scans, FIN scans, UDP and ICMP "smurf" attacks, bogus TCP flags, TCP SYN scans, TCP "Xmas" scans, ICMP ping floods, UDP scans, and IP fragment attacks. iplog is able to run in promiscuous mode and monitor traffic to all hosts on a network. iplog uses libpcap to read data from the network and can be ported to any system that supports pthreads and on which libpcap will function.
Isoqlog is an MTA log analysis program written in C. It is designed to scan qmail, Postfix, Sendmail, and Exim logfiles and produce usage statistics in HTML for viewing through a browser. It produces a "top domains" statistic according to sender, receiver, total mails, and bytes, and keeps the main domain mail statistics with regard to day's top domain, and top users values for per day, per month, and per year.
Jhead is a command line driven utility for extracting digital camera settings from the Exif format files used by many digital cameras. It handles the various confusing ways these can be expressed, and displays them as F-stop, shutter speed, etc. It is also able to reduce the size of digital camera JPEGs without loss of information, by deleting integral thumbnails that digital cameras put into the Exif header. If you need to add Exif support to a program, this is a simple program to cut and paste from. Many projects, including PHP, have reused code from this utility.