As Bloomberg News put it today in a story about Alpha, some mines must die for others to live. And some companies will also die. CONSOL Energy Inc. (NYSE: CNX) is the largest coal producer by market cap, but its survival plan is based on becoming a natural gas producer.So far that has been only a partial success because natural gas prices are so low.nd some companies will also die. CONSOL Energy Inc. (NYSE: CNX) is the largest coal producer by market cap, but its survival plan is based on becoming a natural gas producer. So far that has been only a partial success because natural gas prices are so low.
From the server-side firewall's standpoint, to support passive mode FTP the following communication channels need to be opened: 1  FTP server's port 21 from anywhere (Client initiates connection)  FTP server's port 21 to ports > 1023 (Server responds to client's control port)
How the TCP Port 21 Works With FTP. The File Transfer Protocol Uses Port 20 and 21. The File Transfer Protocol (FTP) provides a means to transfer information online, much like how the Hypertext Transfer Protocol (HTTP) is used through a web browser. FTP, however, operates on two different TCP ports: 20 and 21.