Ftp over SSH port forwarding

Applications IP Networking
1

Hi,
I'm trying to connect ftp over ssh port forwarding to a sever(UnixC) behind FireWall(F/W). here's my env and question.

UnixA(SSH Client) ----F/W ---- UnixB(SSH Svr) ---- UnixC (FTP, 21)

UnixA wants to connect ftp service of UnixC via SSH port forwarding on UnixB.

Unix A, terminal
$ssh -L10021:UnixC:21 ID@UnixB

Logged in UnixB with SSH and from new session on UnixA I tried these commands below.

% telnet localhost 10021
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Connection to localhost closed by foreign host.
% ftp localhost 10021
Connected to localhost.
421 Service not available, remote server has closed connection
ftp>

2

Please use code tags as required by forum rules!

Is FTP_ID a valid user on UnixB ? And what user are you logging into on UnixC ?

3

sorry, FTP_ID gave u confused. updated original question.

ID@ UnixB is valid, i can do ssh login to UnixB from UnixA with ID.
FTP_ID @ UnixC is valid as well. i can access from unixB to unixC with FTP_ID

4

So how in your forwarding session does UnixB know what user to login to on UnixC ?