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500 'CLNT': command not understood by proxy

Posted: Fri Jan 20, 2012 1:06 pm
by Ralph
Hello,

we have tried everything on our Wing FTP Server and on our Firewall.
We want that our Wing FTP Server (FTP Protocol) is reachable over active and passive mode. But this did not work, only one mode is avaiable active or passive. If active is available, we cant log on over passive we are getting the following error:
500 'CLNT': command not understood by proxy

Any idea? Thanks!!

Re: 500 'CLNT': command not understood by proxy

Posted: Fri Jan 20, 2012 2:14 pm
by FTP

Re: 500 'CLNT': command not understood by proxy

Posted: Fri Jan 20, 2012 2:40 pm
by Ralph
Thanks for the link. But we don`t use smartftp client.
We have a FTP Server on Unix (proftpd) and wing ftp on Windows. If we connect from a client to the unix ftp server active / passive works fine, if we connect to the wing ftp server from the same client only active works (passive CLNT error).
Both servers are in the same firewall group object.

Re: 500 'CLNT': command not understood by proxy

Posted: Fri Jan 20, 2012 3:27 pm
by FTP
This issue is caused by your firewall, with your description, it seems your firewall just equals to a proxy server, and it could not recognize a few standard FTP commands, like "CLNT", "MLSD", and the real key issue is it could not recognize the command "MLSD", then it can't do the FTP listing.

So you can solve it on your proxy server (firewall) side or client side, on the proxy server side, I guess there is an option to support the standard FTP command "MLSD", otherwise, you must change something on the client side.