Can I run my own FTP sever on cloud9 terminal and how can I contact it




I am quite a newbies and I write a simple FTP server on Cloud9. While I ran it on terminal I found that I cannot contact it with another terminal

I tried the command: open localhost
but it won’t work.
also, I use the ifconfig to the ip address of my workspace and contact it with terminal FTP client(which is the lftp)