Main reason netcat stays running until the *network* side closes. The 'standard input EOF' problem, so one must introduce calculatedĭelays in driving scripts to allow network output to finish. You may be asking 'why not just use telnet to connect toĪrbitrary ports?' Valid question, and here are some reasons. Sending large amounts of data that way, but it's still a useful capability UDP, as the 'U' implies, gives less reliableĭata transmission than TCP connections and some systems may have trouble 'udp telnet-like' application you always wanted for testing your In either mode, shutdown can beįorced after a configurable time of inactivity on the network side.Īnd it can do this via UDP too, so netcat is possibly the 'client' or 'server' mode - it still shovels data backĪnd forth until there isn't any more left. With minor limitations, netcat doesn't really care if it runs in Netcat can also function as a server, by listening for inboundĬonnections on arbitrary ports and then doing the same reading and writing.

Note that this behavior isĭifferent from most other applications which shut everything down and exitĪfter an end-of-file on the standard input. Network side of the connection shuts down. Is then sent to the host, and anything that comes back across the connection In the simplest usage, 'nc host port' creates a TCPĬonnection to the given port on the given target host. Supplied long ago as another one of those cryptic but standard Unix tools. Netcat, or 'nc' as the actual program is named, should have been At the same time, it is a feature-rich networkĭebugging and exploration tool, since it can create almost any kind ofĬonnection you would need and has several interesting built-in capabilities. Reliable 'back-end' tool that can be used directly or easily drivenīy other programs and scripts. Network connections, using TCP or UDP protocol. nc -l -p port DESCRIPTION ¶ netcat is a simple unix utility which reads and writes data across

Nc netcat options