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Folks over at SO couldn't answer this, so I am posting over here. I need to do an FTP over SSL to a FileZilla Server running on a Windows server from an AIX Unix clien. I have the Host name of the destination server, the user id and password, and an SSL certificate. I am not sure how to install that certificate in AIX. When I do an ftp command (using the below code) from Unix it does connect successfully to the Filezilla server and I am able to do get and or mget. But, I am not sure if that is happening over SSL since I haven't installed the SSL Certificate yet. Do I need to install the Certificate in the Unix box (AIX)? if yes, then how? (specific steps and commands) and how to utilize the installed SSL certificate to do FTP after the installation?

$ ftp XXX.XXX.XXX.243
Connected to XXX.XXX.XXX.243.
220-FileZilla Server version 0.9.24 beta
220-written by Tim Kosse
220 Please visit http://sourceforge.net/projects/filezilla/
Name (XXX.XXX.XXX.243:littercat): joyride
331 SSL required
230 Logged on

Note: SSH (SFTP/SCP) is not an option and it has to be FTP over SSL/TLS only (From AIX UNIX to Windows FileZilla). AIX version 5.3. Third party tools cannot be used (eg. cURL etc.)

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up vote 1 down vote accepted

The standard AIX ftp client does not support SSL or TLS. I'd be very interested if you find a way to get this going without 3rd party tools.

You can grab lftp from several sources ... we have used that in production successfully for a few years now on AIX 5.3. I've used the rpm available here lftp rpm for AIX, as well as compiling from source lftp download, although the latter can take a bit of extra work for things like GNUtls.

Newer versions of AIX 6.1+ include a secure option for the FTP client to use TLS.

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I did find a way to do it through some basic Java code and using Apache Commons-net library, but am stuck there too, I posted a question at SO stackoverflow.com/questions/9950531/…. – Ann Jawn Mar 30 '12 at 21:19

For FTPS you should only need to install the certificate on the server. When you log in, the client should provide information about the certificate and ask you whether or not you want to accept it. The behaviour is client specific though.

I don't know if AIX 5.3 FTP supports SSL.

It is possible to force Filezilla to require TLS on login.

"Edit", "Settings", "Allow explicit FTP over TLS", "Disallow plain unencrypted FTP"

also in your users' setting,

"Force SSL for user login"

If TLS is forced and the AIX 5.3 FTP client can log in, then you're pretty sure that the connection worked. There should be commands in the client to inspect the certificate.

If you're paranoid (it doesn't hurt to be paranoid), run Wireshark on your Windows server to inspect port 20/21 for unencrypted traffic.

Attached is a screenshot of WinSCP (using FTP+TLS/SSL mode explicitly) asking me to accept a self-signed certificate for TLS.

enter image description here

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Thanks. but unfortunately the native AIX 5.3 libraries do not support FTP over SSL/TLS. Third party tools are the only way. – Ann Jawn Mar 30 '12 at 21:18

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