Re: Secure connection error, return code 6000 (FTP)

[Pete Helgren <pete@xxxxxxxxxx>]

Greg,

The issue might be that the third party isn't using the full letsencrypt 
certificate OR the ftp server isn't configured to use the full chain.  
My Letsencrypt certs all have the intermediates included so either the 
3rd party FTP server isn't configured correctly, or pulling the full 
chain isn't supported or they are "peeling off" just the certificate 
part of fullchain.pem  AFAIK, Letsencrypt always included the full chain 
in fullchain.pem which is the standard file delivered by Letsencrypt.  
All you need is the root.

Pete Helgren
www.petesworkshop.com
CISSP - MSCM
GIAC Cloud Penetration Tester
AWS Certified Cloud Practitioner
Microsoft Certified: Azure Fundamentals

On 3/31/2026 10:59 AM, Jack Woehr via MIDRANGE-L wrote:
> Gemini types faster than I do.
> In a standard TLS handshake, the server is supposed to send its own certificate plus any intermediate CA certificates required to link its certificate back to a trusted Root CA.
>
>    *
> If the server sends the full chain: Your trust store only needs the Root CA. The client receives the intermediates from the server, verifies the signatures up the chain, and finds the Root in its local store to finalize trust.
>    *
> If the server only sends its leaf certificate: The connection will fail unless the client has the intermediates locally to fill in the "missing links."
>
> ________________________________
> From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> on behalf of Stefan Skoglund <stefan.skoglund@xxxxxxx>
> Sent: Tuesday, March 31, 2026 09:52
> To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
> Subject: Re: Secure connection error, return code 6000 (FTP)
>
> Why import the intermediary CA's certs ?
>
> That isn't really needed.
>
>
>
> Jack WoehrIndependent Consulting Programmer 303-847-8442 jack.woehr@xxxxxxxxxxx www.procern.com Stay Connected!Upgrade your IT state of mind!NON-DISCLOSURE NOTICE: This communication including any and all attachments is for the intended recipient(s) only and may contain confidential and privileged information. If you are not the intended recipient of this communication, any disclosure, copying further distribution or use of this communication is prohibited. If you received this communication in error, please contact the sender and delete/destroy all copies of this communication immediately.