knocker(1) An easy to use network security port scanner


knocker --host <host> [OPTION]


knocker is a simple and easy to use TCP security port scanner written in C using pthreads which is able to analyze hosts and all of the different services started on them.


-H, --host
host name or numeric Internet address to scan
-P, --port
port number to scan (single port scan only)
-SP, --start-port
port number to begin the scan from
-EP, --end-port
port number to end the scan at
uses the last scanned host as target
performs again the last port scan
-q, --quiet
disable console output and logs to file.
-lf, --logfile <logfile>
log the results to a specified file.
-nf, --no-fency
disable fency output
-nc, --no-colors
disable colored output
let the user configure knocker
-h, --help
display this help and exit
-v, --version
output version information and exit


To run this program the standard way type:

knocker --host

If you want to specify a port range to scan:

knocker --host thehost --start-port 1 --end-port 2600


knocker -H thehost -SP 1 -EP 2600

To scan a single port:

knocker -H thehost --port 21

To run this program not using colors (if your terminal does not support colors):

knocker --host --no-colors

To run this program run in background and have the results written in a log file:

knocker --host --quiet &


The latest version of this program can be found at


See the BUGS file in the knocker source package for a list of known bugs. Report bugs to <[email protected]>


knocker is written by Gabriele Giorgetti <[email protected]>


Copyright © 2001,2002 Gabriele Giorgetti
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.