Topic: FTP over SSL sever problems

[Sandra]

As some members already know, I run a server on a spare pc for my friends to exchange and share files between us.
Its an FTP server and with security in mind I decided to set the FTP over SSL explicit option on it.

I had found a free FTP program that worked with SSL FTP servers and had sent or given the link for downloading it to the users of my server.

A couple of users found that they could connect to my server but not display any of its contents, these were only the ones who were using a router.

This puzzled me for a while until I found out about the CCC option ( Clear Command Channel).

Using a SSL ( Secure Socket Layer) server means that all the data is encrypted between the server and the client pc, both ways.

The login details are encrypted and once a user is logged in a command is sent from the server to that users pc that requires the correct response in return and sends the key necessary to decrypt the encrypted files after transferring to or from the server.

Anyone on a NAT enabled router (are there any these days that arent ? ) network can log on ok but the NAT of the router cant understand the encrypted command from the server and so gets disconnected by the server after the timeout period as the server hasnt received the correct response from the users pc.
Modem users whether on ADSL, Cable or Dial Up were able to connect without problems.

Using the CCC option on the server program overcomes this option while maintaining the encryption of the original log in process and the actual files being transferred, it just enables an unencrypted command to be sent to the users pc so that the correct response can be returned to the server.

However this means that the FTP program that the users have has to have the allow CCC option also.
I havent found any free programs that have this feature in, apart from one that ran from the command prompt and looked quite complicated to set up  

Fortunately a friend who has WS_FTP Pro v 9.01 found that his pc will connect through his NAT enabled router and allows connection, listing of the servers contents and transferring of files

I posted this here to explain a little about SSL, in case anyone is thinking of setting a server up using the added security of SSL and so that they could hopefully avoid some of the problems that its taken me quite a few days to overcome  :roll:

If anyone knows of any free FTP client programs that work with FTP over SSL explicit and allow CCC please post a link on here, as not everyone can afford WS_FTP pro  

[Simon]

I have to say, WS FTP Pro is the best program of it's kind that I have used.

[sam]

you could probably use ssh enabled programs (such as Secure Shell Transfer Client) aswell...I think most of these have that option - though I havent tried it for that exact task