CDDIS - Termination of ftp - Bandwidth Limiting Taking Place

Michael, Benjamin P. (GSFC-61A0) benjamin.p.michael at
Thu Jul 9 17:12:21 UTC 2020

To the UNAVCO community announcements sent out earlier on current actions at CDDIS.  See below.

Dear CDDIS Users,

Reminder that the first step in termination of unencrypted anonymous ftp at CDDIS takes places 1 July 2020.  At that time CDDIS will bandwidth limit ALL IPs to just 1MB/s transfer rates.  The second and third bandwidth reductions will take place as laid out in the original email announcing termination of unencrypted anonymous ftp (see below).  Please give this email widest dissemination to your colleagues.

Instructions and example links are listed below in the original email.  Pay particular attention to needing a .netrc file in some examples.  Please address questions to support-cddis at<mailto:support-cddis at>


Patrick Michael
Crustal Dynamics Data Information System (CDDIS)
NASA-Goddard Space Flight Center
Greenbelt, MD 20771
Patrick.Michael at<mailto:Patrick.Michael at>

Dear CDDIS Users


For more than two years now CDDIS has been warning our user community about the eventual termination of anonymous ftp to the CDDIS archive.  On 31 October 2020, unencrypted anonymous ftp access will officially be discontinued at CDDIS.  CDDIS will bandwidth limit ALL unencrypted  ftp service starting the summer of 2020.  CDDIS will implement bandwidth limits and final discontinuation of unencrypted ftp service in the timeline below.

  1.  1 July 2020 – all unencrypted ftp service will be bandwidth limited to 1MB/s
  2.  10 August 2020 – all unencrypted ftp service will be bandwidth limited to 250KB/s
  3.  1 October 2020 – all unencrypted  ftp service will be bandwidth limited to 50KB/s
  4.  31 Oct 2020 – all unencrypted ftp service will be permanently discontinued at CDDIS

CDDIS is STRONGLY recommending all users begin to transition to use https ( as the preferred method of access to the CDDIS archive.  Download procedures can be found at:, along with a Frequently Asked Questions (FAQ) link and links of how to use cURL, wget and Python (

CDDIS has also made available ftp-ssl (<>) as a secondary method to access the archive.  In some cases the use of ftp-ssl may make the conversion of existing scripts easier than using https.  Examples of how to use ftp-ssl are listed at:

CDDIS will NOT be changing the archive structure.  So the locations that you are using to access files will stay the same.  Though a prefix in the URL might be needed, (i.e. /archive for the https method) or a new host (for ftp-ssl).

CDDIS currently supports approximately 300,000 users and served out almost 2 billion files in 2019.  We understand that this change can have a significant impact on some of our users and have tried to make this process as easy as possible.  Unfortunately this change is mandated by the US Government and outside of CDDIS’s control.  If there are questions or comments, we ask that you address them to support-cddis at<mailto:support-cddis at>  and not directly to any CDDIS staff member.

So in summary:

  1.  Anonymous ftp service will be discontinued 31 October 2020.
  2.  Transition to https or ftp-ssl needs to begin NOW
  3.  Questions should be addressed to support-cddis at<mailto:support-cddis at>

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