Computer A (assumed that ip is 184.108.40.206)can ftp the host 220.127.116.11.
ftp 18.104.22.168 Connected to 22.214.171.124. 220 ftp.debian.org FTP server Name (126.96.36.199:debian8): anonymous 331 Please specify the password. Password: 230 Login successful. Remote system type is UNIX. Using binary mode to transfer files.
Computer B (my local pc) can not ftp the host 188.8.131.52. Let's build a ssh tunnel with ssh command this way:
ssh -L -f -N localhost:2121:184.108.40.206:21 email@example.com
The ssh tunnel between my local pc and Computer A (220.127.116.11) was connected after password to login into 18.104.22.168.
Then to input the command on my local pc console:
ftp localhost:2121 ftp: localhost:2121: Name or service not known
What is the matter with my ssh tunnel?