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KNOCKER(1) General Commands Manual KNOCKER(1)


knocker - 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.


host name or numeric Internet address to scan
port number to scan (single port scan only)
port number to begin the scan from
port number to end the scan at
uses the last scanned host as target
performs again the last port scan
disable console output and logs to file.
log the results to a specified file.
disable fency output
disable colored output
let the user configure knocker
display this help and exit
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 <>


knocker is written by Gabriele Giorgetti <>


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.

May 24, 2002