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ncat: netcat -q secs option not supported #2422

pothos opened this issue Jan 9, 2022 · 1 comment

ncat: netcat -q secs option not supported #2422

pothos opened this issue Jan 9, 2022 · 1 comment


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pothos commented Jan 9, 2022

Describe the bug
Both nc.traditional and nc.openbsd have a -q secs quit after EOF on stdin and delay of secs parameter which ncat does not support. This fails the command invocation when ncat is used as symlinked drop-in for nc.

To Reproduce
echo | ncat -q 1 53 results in ncat: invalid option -- 'q' Ncat: Try '--help' or man(1) ncat for more information, usage options and help. QUITTING.

Expected behavior
Same as echo|nc.traditional -q 1 53 would lead to exiting after one second without failure and nothing printed.
The -q 1 timeout kicks in becase stdin is closed after echo printed its single empty line.

Version info (please complete the following information):

  • OS: Linux 5.16rc8
  • Output of ncat --version: 7.80

Additional context
This is a compatibilty problem occuring on systems that try to stop shipping traditional or OpenBSD netcat, .e.g, on Flatcar Container Linux where nc is a symlink to ncat.

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Thanks for requesting this feature. The -q option is indeed unimplemented, as documented in our Ncat/netcat compatibility guide. I will label this issue as a feature request so we can prioritize it accordingly. Pull requests are also welcome.

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