In Windows, I go to command line and 'telnet ' to check the port. How to do the same in Unix?
It seems some people using 'tcpdump port ' commands. Is this monitoring the real time traffic? Thanks.
You may not have nmap installed at the moment, but it is in just about all distros standard repositories. For debian or ubuntu variants
You could also just use the same
If you're using bash, then the man pages state that you could write to /dev/tcp/HostNameOrIP/port. I've used this a few times and if the remote port is open, then there is no response. If the system cannot connect to the remote port, then it states the reason