-- nc -zv <host> 80This happened at work, when our buildkite agents didn’t have telnet installed but had nc. We were trouble-shooting a network issue and it was critical to determine whether we could connect out vs the listener service being blocked.
nc -zv www.google.com 80
Connection to www.google.com 80 port [tcp/http] succeeded!
telnet is a useful tool for trouble-shooting whether its possible to connect to a remote server listening on a particular port. But what happens when your host doesn’t support the telnet command? nc article here