Ncat/EOF behavior

This page describes how Ncat handles End Of File when reading from various places. We wish to be consistent internally and to be consistent with Traditional and OpenBSD netcats when they agree with each other.

Behavior

Client/Connect Mode (TCP)

EOF on:	stdin	socket
no options	closes socket write, keeps running	closes stdout, keeps running
--send-only	quits	N/A, does not read from socket
--recv-only	N/A, does not read from stdin	quits

Server/Listen mode (TCP)

EOF on:	stdin	socket
no options	closes socket write, keeps running	closes stdout, quits
--send-only	quits	N/A, does not read from socket
--recv-only	N/A, does not read from stdin	quits

Other considerations

--no-shutdown

Ncat supports the TCP idea of half-open connections. When EOF is read on stdin, Ncat calls shutdown on the socket in the "write" direction. The --no-shutdown option can be used to prevent this behavior, and may be necessary in some circumstances in order to prevent Ncat from closing entirely while there is still data to be received.

--keep-open

The --keep-open or -k option can be used in server mode to run a simple forking network server. In this case, the tables above may not describe the behavior of the forked processes.