IP Networking

Hi,

I have a conenction to remote server that I'm sending files too via FTP.

The problem I have is that when the file gets delivered it is 0 (zero) size.

I've manually connected and logged on. The only command I can successfully execute is pwd. When I do a dir or a put command it will hang until the connection times out.

I have tried extending the time, ensured the permissions are set and that there is disk space. Any ideas how I can write a zero length file, list the path but not be able to put a full file or list the directory?

Thanks in advance

Sounds like an issue on the FTP side, something is not setup properly, since you cannot execute simple commands. What is the FTP implementation and the OS ?

Isn't ftp setup to encode the transmission to ASCII? Try send this as a binary file - that is more thorough.
ftp> bin

Hi,

We now have a number of feeds that are being affected???? going to various OS types (Windows, SUN, HP) at various hosting sites.

I'm thinking that there may be a firewall issue on the return leg (maybe ) that is rejecting the return packets (again maybe not 100% sure how the ftp protocol works).


If I issue a "put" command does the recieving end issue an accept packet before we transfer data? if it does then how is it possible to issue a pwd and get a response????

Cheers and beers

Try to use ftp with "-v" option.
It gives the full details and try to find out what went wrong.

Yes you are right. As FTP control and data connections are different it is possible that firewall is not doing FTP "specific" NAT/Proxy.
In such cases working in "passive" mode FTP helps.
Before tranmission just type "passive" command on ftp> prompt

sounds like a data connection problem. when you try to upload a file, a few things happen.

1. server creates empty file if it does not exist on server

2. server opens data port to receive file transfer.

3. data received is saved to file opened in step 1.

based on your description it sounds like step 1 is completing, hence not a permissions issue. However the server is unable to receive data from the client. This is likely a firewall issue (client side if using non-passive/ server side if using passive) or a server configuration issue e.g. server is listening for passive connections on internal IP instead of external IP (common mistake). A debug log of your FTP session would help to answer the question. Use "-v" option as mentioned previously.