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FTP Directory Listing Issue

Posted on 2011-02-24
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Last Modified: 2012-05-11
Hi,

I have tried connecting to one of our client's FTP and I can't see any of the folder structure.
But the client insisting that the folder structure is there,
I want someone to help me to troubleshoot this issue?


thisi is the filzilla log info while I was tried to connect to their FTP site.

Status:      Connecting to 1xx.2xx.3xx.1xx:21...
Status:      Connection established, waiting for welcome message...
Response:      220 NX-PXX1 FTP Server - Welcome
Command:      USER testftp
Response:      331 Please specify the password.
Command:      PASS ********
Response:      230 Login successful.
Command:      SYST
Response:      215 UNIX Type: L8
Command:      FEAT
Response:      211-Features:
Response:       EPRT
Response:       EPSV
Response:       MDTM
Response:       PASV
Response:       REST STREAM
Response:       SIZE
Response:       TVFS
Response:       UTF8
Response:      211 End
Command:      OPTS UTF8 ON
Response:      200 Always in UTF8 mode.
Status:      Connected
Status:      Retrieving directory listing...
Command:      PWD
Response:      257 "/"
Command:      TYPE I
Response:      200 Switching to Binary mode.
Command:      PASV
Response:      227 Entering Passive Mode (1XX,2XX,3xx,1xx,253,41)
Command:      LIST

Thanks
la
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Question by:la-tempestad
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Expert Comment

by:abhijitmdp
ID: 34969452
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Author Comment

by:la-tempestad
ID: 34969563
This is not our FTP server?
it's one of the clients(3rd party).

So you reckon it is badly configured FTP server causing it?
any other tips which I can ask the client to do make it visible(directory tree)?

thanks
la
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Author Comment

by:la-tempestad
ID: 34969609
Another thin which I noticed just now,I can see all the folders if I use CMD prompt for FTP.

that shows these folders are genuine and I can connect using the CMD but not by Filezilla.Hmm..
I am not getting it?

thanks again
la
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Accepted Solution

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AlexPace earned 500 total points
ID: 34969746
When you can connect but not get a directory listing or transfer files that means that the FTP control channel is working fine but the FTP data channel is blocked.

The log shows that your FTP client sent PASV to inform the server that the client wanted to do a passive mode transfer.  The last two numbers in the server's response are the port number on which the client should connect to do the transfer: 253,41

To decode this, first convert the two numbers to hex
253  = FD
41 = 29

Then combine them to get a hex value of FD29

Now convert back to decimal:  FD29 = 64809

So the FTP server responded to your request for passive mode by inviting you to connect to it on port 64809.  You didn't connect.  If other people do transfers to this server in passive mode then ask your network administrator to check for a rule on your firewall that prevents your outgoing connection on this port.  You may also be able to contact the administrator of the remote server and ask them if they use a certain range for passive mode... this way you can tell your network admin guy a range of ports to open instead of just opening them all.

An easy thing to check before doing any of that is just see if it can work in active mode.
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Author Comment

by:la-tempestad
ID: 34969884
I was reading another forum,I just found out it is something to do with the client's firewall blocking the connections coming from filezilla.exe.

this is what the forum recommending----------------
Basically the server needs to have a passive ftp port range opened in its own firewall and then FTP Server also needs to be configured to use this passive port range.

I am not quite sure how you wanted to do that on the firewall.
any helps would be appreciated.

regards
la
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Expert Comment

by:AlexPace
ID: 34970025
Chances are good that you are not the first person to connect to this particular server so although it is possible that the problem is the firewall configuration on the remote side, it is more likely to be either a firewall on your side or that the remote server doesn't want to use passive mode at all.  

If active mode doesnt work for you then ask your local administrator if any firewall rules prevent you from making outgoing FTP data connections to the remote server on port 64809 because thats what your FileZilla tried to do and failed.

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Author Comment

by:la-tempestad
ID: 34971115

Changed the Transfer mode from passive(recommneded) to Active solve the issue.

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Author Comment

by:la-tempestad
ID: 34971174
Why it worked when I changed to Active mode.
I have a feeling now the client's firewall is not bothered about checking the traffic as it is controlled by the client pc/port itself for Active mode.
Am I right?

also I have selected Ask for OS for the external IP address.

Thanks
la
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Assisted Solution

by:AlexPace
AlexPace earned 500 total points
ID: 34971321
Yes in active mode the client tells the server which port to use and then the server initiates a connection back to your client.  Look in the client's log for the PORT command... those last two numbers can be converted as I showed above to learn which port your client requested that the server connect to on your computer.

Also be aware that some firewalls are "protocol aware" about FTP connections.  This means that they are able to inspect the contents of the FTP control channel, notice that your client sent the PORT command, and then are able to unblock the requested port on the fly to allow the data channel connection.  
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