Implicit SSL, can connect but no directory listing?!

Hello, I'm trying to connect to a Serv-U 5.x FTP server using SmartFTP's implicit SSL. The server is running Windows XP Pro SP2.

The server uses port 21 (port forwarding on the remote network forwards port 21 to the FTP server on its LAN), and I can connect and authenticate fine (encryption keys are exchanged, etc.) but as soon as I try to download a directory listing, I get a connection closed while in Active mode, or a timeout while in Passive mode.

Here's what I see in SmartFTP:





    SmartFTP v1.5.990.11



    Resolving host name "myhost.org"



    Connecting to 1.2.3.4 Port: 21



    Connected to myhost.org.



    Connected. Exchanging encryption keys...



    Session Cipher: 128 bit RC4



    TLS encrypted session established.



220 Ready...



    USER myusername



331 User name okay, need password.



    PASS (hidden)



230 User logged in, proceed.



    SYST



215 UNIX Type: L8



    TYPE I



200 Type set to I.



    REST 0



350 Restarting at 0. Send STORE or RETRIEVE.



    PWD



257 "/" is current directory.



    CWD /



250 Directory changed to /



    PWD



257 "/" is current directory.



    PBSZ 0



200 PBSZ command OK. Protection buffer size set to 0.



    PROT P



200 PROT command OK. Using private data connection.



    PORT 192,168,21,34,6,121



200 PORT Command successful.



    LIST -a



150 Opening ASCII mode data connection for /bin/ls.



426 Data connection closed, transfer aborted.



    Automatic failover of data connection mode from "Active Mode (PORT)" to "Passive Mode (PASV)".



    PASV



227 Entering Passive Mode (192,168,123,97,7,168)



    Opening data connection to 1.2.3.4 Port: 1960



    LIST -a



    A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.



    Timeout (240s).



[/b]

Here's my system information:




+- System -----------------------------



Microsoft Windows XP Professional 



Service Pack 2 (Build 2600)







CPU Speed         : 2393 MHz



Total Memory      : 457712 KB



Free Memory       :  52364 KB







+- SmartFTP ---------------------------



Version           : 1.5.990.11



Time Stamp        : 2005-09-13 23:37:46







+- Application DLL --------------------



Controls.dll      : 1.6.990.11



sfFTPLib.dll      : 1.5.6.2



SmartHook.dll     : 1.0.2.1







+- Language ---------------------------



SmartFTP.exe      : 1.5.990.11







+- System DLL -------------------------



unicows.dll       : 1.0.3703.0



shell32.dll       : 6.00.2900.2620 (xpsp_sp2_gdr.050225-1820)



shlwapi.dll       : 6.00.2900.2668 (xpsp_sp2_gdr.050430-1553)



comctl32.dll      : 6.0 (xpsp_sp2_rtm.040803-2158)



riched20.dll      : 5.30.23.1221



schannel.dll      : 5.1.2600.2180 (xpsp_sp2_rtm.040803-2158)







+- Internet Explorer ------------------



Version           : 6.0.2900.2180







+- Winsock ----------------------------



Winsock           : 2.2




Any help would be greatly appreciated!

Some more info, this FTP setup works fine for me for Clear (non-SSL) connections.

Maybe I need to open up additional ports, even though for this "implicit" SSL only 21 is specified? Or is it better to go with "explicit" mode? 8O

Found the solution.