Knocker is a simple, versatile, and easy-to-use TCP security port scanner written in C, using threads. It is able to analyze hosts and the network services which are running on them. Knocker it is available for Linux, FreeBSD, many Unix platforms, and Windows 95/98/2000. Both a console version and a GTK+ version are available.
| Tags | Internet Security Networking Monitoring |
|---|---|
| Licenses | GPL |
| Operating Systems | POSIX Linux BSD FreeBSD HP-UX Windows Windows Windows |
| Implementation | C |
Recent releases


Changes: This version fixes a problem in the 0.7.0 release that was causing knocker not to build on non-Linux OS (FreeBSD, OpenBSD, HP-UX etc).


Changes: A new option to display the program output in a "no-fency" mode was added, as well as a --configure option. The colored output code has been improved, and no longer causes the background color to change if knocker is executed in an X11 terminal. The text is now correctly displayed on transparent background terminals. This release adds the options --last-scan, to perform the last port scan again, and --last-host, which puts the last scanned host as the target.


Changes: A complete rewrite of GTK-knocker from scratch, with the GUI interface redesigned using GLADE, a fix for the "Freeze" bug (the GUI interface is no longer freezing during long scans), fixes for start/stop scan buttons, and a new ability to log the scan results to file.


Changes: A serious bug that was preventing knocker from scanning a number of ports greater than 1023 was fixed. Previously, all ports scanned after the 1023rd one were reported as closed. Another bug that was causing knocker to segfault before exiting if a hostname couldn't be resolved was fixed.


Changes: Showing a more accurate elapsed time in the port scan result, a fix for a bug that caused knocker to segfault if a host was not specified after the --host option, and new Win32 Winsock code to make knocker work and build natively on Win32 platforms.