See if netstat is installed:
If not, install it (for Linux):
Shows all connections:
Shows all connections on port 22 (SSH): using grep
Use "| grep" to filter the results:
Shows how many connections are active on port 22 (SSH):
Use "| grep 22" to filter the result to port 22 and "| wc -l" to show the number of lines (in here is number of connections):
Shows all UNIX domain sockets:
Shows all UNIX domain sockets - (If they don't fit on the page use " | more" ):
Shows all active TCP connections:
Shows all active UDP connections:
Shows all listening ports (UNIX domain and Internet connections):
Shows all listening ports (Internet connections):
Shows all listening TCP ports:
Shows all listening UDP ports: