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)
FTP is an underling of TCP and shuttles files back and forth between FTP server and FTP client. Because FTP requires that two ports be open--the server's and the client's--it facilitates the exchange of large files of information. First, you as client make a TCP control connection to the FTP server's port 21 which will remain open during the transfer process. In response, the FTP server opens a second connection that is the data connection from the server's port 20 to your computer.