IBM Support

Changes to Fix Central bulkFTP download method

Question & Answer


What has changed with the Fix Central "bulk FTP" download option?


Fix Central is modifying the "bulk FTP" download option to use secure FTP(FTPS).

As of February 2017 all downloads using "bulk FTP" will require a secure FTP client connection.
As of June 2017 SFTP (FTP over SSH) has been enabled along with FTPS for external customers only.

Why is Fix Central moving to secure FTP?

IBM and our customers prefer encrypted communication. We have been asked by customers, and see the benefit of, moving to an encrypted SSL(TLS) based FTP protocol.

What will I see different on Fix Central?

In the Download options page, if the product download supports the "Download using bulk FTP" option, will now change to "FTPS". You will now also be given a temporary, order specific, user ID and password which will be needed to access the fixes through FTPS. For fixes that do not require entitlement checks, you can still use the anonymous ID. In both cases the browser based "FTP download location" button now will go away, as browsers do not support FTPS. And you will have to use an SSL(TLS) enabled FTP client to be able to download fixes from the FTP server location provided. Exception: For some unique individual AIX fixes, there are still some available links using regular FTP. These will go away at some point in the future.

Does Fix Central recommend specific FTPS clients?

No, any ftp client that supports SSL(TLS), passive will work.
Update June 2017: any clients supporting SFTP will now also work.

Check out the section How can I debug FTPS? to see tips for a couple of the most common clients.

When will this change take effect?

Starting February 2017, you will notice the "bulk FTPS" results page will be referencing the need for you to use FTPS clients, and will provide you the temporary user ID and password.

Update: This was originally delayed from an initial plan of January 2017.

What error might I see?


  • "remote host did not respond within the timeout period."
  • "Error: Connection timed out after 20 seconds of inactivity"
  • "Error: Failed to retrieve directory listing"
  • "Timeout detected. (data connection)"
  • "Could not retrieve directory listing"
  • "Error listing directory"
  • "Listing directory / failed"
  • "450 LIST: Connection timed out. Please contact your web hosting service provider for assistance."
  • "Timeout (????? ms) occurred on receiving server response."
  • "Error 0x80043103 - Connection timeout."
  • "A remote host refused an attempted connect operation.
    can't find list of remote files, oops"
  • "Unable to make a connection. Connection timeout."
    The above error messages may be received when using the "get", "mget", or "dir" commands in ftps.

    If the client tries to connect but the "data" connection is being blocked by firewall, then depending on the client, you will receive a message similar to one of the above. Please contact your firewall administrator and send them information found here:
  • "Error with certificate at depth 1"
    There is a known OpenSSL bug seen by some users of the AIX ftp client. It was resolved with the latest OpenSSL filesets. You may see a slightly different error, but the error will be about a failed certificate verification. If you get this error please visit the following URL and upgrade to the latest version of OpenSSL.

What is FTPS?

FTPS is an extension of FTP which uses SSL/TLS encryption and an alternative "data" port for downloads. But there are several flavors/modes that may be used.

FTPS is implemented on these fix download servers using "explicit" and "passive" mode. This means that the initial communication or "command" channel will be opened on port 21. After the initial "command" communication on port 21 the server will tell the client on which port to communicate for "data". In this implementation the port is random and between 65024-65535. Therefore client firewalls must allow outbound (TCP) traffic on that range of ports to enable FTPS download of fixes from IBM.

FTPS is sometimes confused with SFTP, but SFTP uses ssh rather then FTP.

The "explicit" mode refers to the fact that the client uses the regular FTP port 21 for the initial communication. If your client is trying to communicate using "implicit" mode FTPS, it may be trying to open the initial "command" port using 990. If you get an error about not being able to communicate using port 990, it means your client is trying to run "implicit" mode. Please try and change that, or on some clients just change the port to 21.

The initial "command" connection from your client is initiated outbound on port 21. This is the same direction and port used for regular FTP and therefore should not be causing you a problem if you have used FTP to communicate for fix downloads in the past. The only difference now is that IBM now expects encrypted data to be sent in. If you are not using FTPS, you will receive a message that talks about encryption being required. Some examples of clients showing this failure include:

550 SSL/TLS required on the control channel

If the initial "command" communication and login succeeds, then the next important factor is that the client and server start talking in passive mode. For most FTPS clients they will automatically negotiate with the download server and default to "passive" mode. For AIX client using "ftp -s" the user must manually enter the "passive" command immediately after logon.

After successful logon, and entering "passive" mode, if you enter a "dir" command you should see something like this:

227 Entering Passive Mode (129,35,224,115,254,213).
150 Opening ASCII mode data connection for file list
TLSv1/SSLv3 ( AES256-SHA ), 256 bits
lr--r--r-- 1 tNuMwOLT ftpapp 76 Mar 7 17:54 {Filename deleted for this example}

The above number string is useful information. It can be interpreted as telling the FTPS client to connect to ip: on port (256 * 254 + 213)= 65237...
Your client will then attempt to open an outbound "data" connection to
In the example output above the data connection is successful and "dir" command returns the contents of your current directory. But if the connection is blocked by a firewall, you will get one of the errors listed in the above section: What error might I see?

If that is your error, please contact your network administrators and reference this information: What does my firewall team need to know?

The screen output below is listed here as an example of successful communication using the AIX "ftp -s" command:

--> ftp -s
Connected to
220 ProFTPD 1.3.5b Server (proftpd) []
234 AUTH TLS successful
TLS Auth Entered.
TLS handshake succeeded, though Server signed it's own cert!
Version: 3 (0x2)
Serial Number:
Issuer: C=US, O=GeoTrust Inc., CN=GeoTrust SSL CA - G3
Not Before: Jan 5 00:00:00 2017 GMT
Not After : Mar 6 23:59:59 2018 GMT
TLSv1/SSLv3 ( AES256-SHA ), 256 bits
Name ( tNuMwOLT
331 Password required for tNuMwOLT
230 User tNuMwOLT logged in
200 PBSZ 0 successful
200 Protection set to Private
ftp> passive
Passive mode on.
ftp> dir
227 Entering Passive Mode (129,35,224,115,254,213).
150 Opening ASCII mode data connection for file list
TLSv1/SSLv3 ( AES256-SHA ), 256 bits
lr--r--r-- 1 tNuMwOLT ftpapp 76 Mar 7 17:54 {Filename deleted for this example}

Can I use SFTP instead of FTPS?

Yes, as of June 2017, SFTP has been enabled for all bulkFTPS paths in FixCentral. Note: IBM employees may have problems using SFTP as the internal IBM network does not have the SFTP connections setup yet for these servers. But from outside IBM network SFTP is working. SFTP is FTP over SSH, while FTPS is FTP over TLS/SSL. They are two very different communication methods. At this time the IBM fix download servers are configured using FTPS and SFTP, but the instructions for each is different, and trying to document each can cause confusion.

What are some alternatives to FTPS?

Along with the bulkFTPS option which requires FTPS or SFTP clients for download, Fix Central also currently supports HTTPS and Download Director. Some products have a few additional options, but these 3 (Download Director, HTTPS, and bulkFTPS) are the major options that are most widely used for all products.

For information on Download Director please visit: Download Director FAQ
For information on HTTPS please visit: HTTP Download FAQ

How can I debug FTPS?

IBM fix download servers are implemented using FTPS (FTP protocol with TLS/SSL encryption and Passive data transfer mode) and SFTP (FTP over SSH) . After reading the section What is FTPS? please check out the tips below for common issues with some of the most popular clients.

Tips for AIX(FTPS) : You must use "ftp -s". You also must immediately, after login, enter the "passive" command. It is also helpful after the "passive" command to then enter "dir" and verify the passive mode is entered and you can see the list of files. If it fails, the "entering passive mode" statement will include information on what port was attempted for the "data" port.

Tips for AIX(SFTP) : example:
sftp (Note: use user ID and hostname given on FixCentral)
mget *

Also please be aware for IBMers inside of the IBM network, this is not enabled yet internally to IBM, hope to enable that soon.

Tips for Filezilla(FTPS): Make sure you are using FTP mode with "FTP over TLS" Encryption option. Use normal "Logon Type" with user ID and password. (note: as of June 2017 SFTP is now enabled)

Tips for Filezilla(SFTP): (note: as of June 2017 SFTP is now enabled) Defaults Choose the Protocol option of "SFTP - SSH File Transfer Protocol". Normal login type and enter User and Password. Also please be aware for IBMers inside of the IBM network, this is not enabled yet internally to IBM, hope to enable that soon.

Tips for WinSCP(FTPS): You need to choose "FTP" protocol with "SSL Explicit encryption", You will need to choose "Port number: 21" . But because the fixes you are downloading may be using symbolic links, WinSCP requires that you go into the Advanced Site Settings and under Environment->Directories you need to clear the "Resolve symbolic links" box. However, you cannot clear this option while your "File protocol" is already set to "FTP". Therefore make sure "File protocol" is set to "SFTP" then go to advanced->Environment->Directories and clear the "Resolve symbolic links". Then go back and change "File protocol" to FTP. All other default options will work.

Tips for wget: The following is an example of using wget to download the bulkFTPS bundle:(replace ????? with the user ID and Password given to you by Fix Central)
wget --ftp-user=????? --ftp-password=????? --no-check-certificate ftps://*
Using -no-check-certificate does bypass encryption and should only be used if you are not concerned about using encryption and certificates to verify authenticity of the communication.

Tips for curl on Red Hat and Cygwin: To get a list of files to download run:
curl --ftp-ssl -u {userid}:{password} 
For each file in the list run:
curl --remote-name-all --ftp-ssl -u {userid}:{password} 
(If -remote-name-all is not available on your version of curl, use -o flag to specify local name for file. Also note that the url has "ftp" and not "ftps". When specifying "ftps" then explicit mode is attempted and port 990 is used. Using "ftp" keeps the initial "command" port being opened on port 21. -ftp-ssl tells it to encrypt the communication.

Tips for FireFTP (Add-on for Firefox):
After installing the FireFTP add-on, in the Firefox browser you can enter "ftps:" and hit enter.
Next click on "Create an account". Complete the host, login and password fields, as received from Fix Central order. On the "Connection" tab click Security and select "Auth TLS(Best)"

What does my firewall team need to know?

(Notice: December 2021 added added info for IBM i fixes)

(Notice: June 2017 added 3rd server to this list)

IBM bulkFTPS method for Fix Central is currently hosted on two servers, but referenced by 3 hostnames:
(, and

When using FTPS the initial communication is over port 21 using SSL/TLS encryption. Then for data command like "dir" or for each "get" operation on a per file basis an outgoing "TCP" communication using a port between 65024 thru 65535 is opened.

SFTP requires port 22 open to following IBM servers. Each of the three servers may resolve to two IP addresses that could be used depending on maintenance and fail over scenarios.

Ports need to be opened to the following IP addresses:

As of July 2021 the FTP download method for IBM i operating system fixes moved to secure FTP methods as well.  The above hosts are not relevant for IBM i downloads.  For IBM i fixes follow the instructions here:  .

How can I request help if I run into any problems?

If you have any problems and need help from the Fix Central team, please use the blue Contact and Feedback button which is floating on the right edge of the Fix Central pages.

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Document Information

Modified date:
28 December 2023