OpenBSD netcat

For a controlled connection, choose client or listening mode, the address family and the destination or local port. OpenBSD’s manual shows data passing between standard input and output, with -N closing the network side after input EOF. Keep timeout behavior explicit: the default is no timeout, and -w is ignored in listening mode. This implementation supports TLS and proxies, but their option combinations have restrictions; TLS cannot be combined with UDP or Unix-domain mode. The manual also warns that UDP scans using -uz always report success regardless of the target’s state. Use the manual matching the installed nc implementation, since packages called netcat can expose different flags. No command here establishes connectivity beyond its chosen endpoint and protocol.