when I make
PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 111/tcp open rpcbind 631/tcp open ipp 646/tcp open unknown
what is the port 646 ?
You should be able to see whats running on that port with
From the comments
This indicates that rpc.statd (PID 2584) is listening on port 646. The rpc.statd process is part of the implementation of NFS.
Since the question has already been answered, I'll provide an answer with a little more background.
Nmap shows open ports by attempting to connect to them. If it receives a positive response, it reports the port as open, and gives a little more information (the
The operating system of the scanned machine knows all about what ports are open, since it has to handle the lower layers of network communication in order to hand the data off to the application (or program) that is listening for it. On Windows, Linux, and most *nix systems, users can get the information about open ports directly from the OS by using the
Nmap is not limited to looking up port information in