Re: How to configure client-side TLS ciphers for streaming replication?

Hi ,

Found an article which might be of help, configuring through  HAProxy as a TLS proxy to control cipher suites.

https://stackoverflow.com/questions/53198588/how-to-disable-specific-cipher-suites-from-haproxy-can-i-do-this-ssl-default
[https://cdn.sstatic.net/Sites/stackoverflow/Img/apple-touch-icon@2.png?v=73d79a89bded]<https://stackoverflow.com/questions/53198588/how-to-disable-specific-cipher-suites-from-haproxy-can-i-do-this-ssl-default>
Can I do this "ssl-default-bind-ciphers no RC4-MD5" - Stack Overflow<https://stackoverflow.com/questions/53198588/how-to-disable-specific-cipher-suites-from-haproxy-can-i-do-this-ssl-default>
How to disable specific cipher suites from Haproxy? All the documents say is to provide a list to be allowed for 'ssl-default-bind-ciphers'. I want to provide only the ones NOT to be allowed. Can I do this "ssl-default-bind-ciphers no RC4-MD5" Reason: I don't want to restrict myself to the ones I put in the list. If the client comes in with a better, faster ciphers suite- I want the ...
stackoverflow.com
Ciphers: https://www.openssl.org/docs/man1.0.2/apps/ciphers.html


Thanks & Regards

Dinesh Nair


________________________________
From: Rob Sargent <robjsargent@gmail.com>
Sent: Tuesday, August 26, 2025 7:25 PM
To: Z xx <xxz030811@gmail.com>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>; pgsql-general@lists.postgresql.org <pgsql-general@lists.postgresql.org>
Subject: Re: How to configure client-side TLS ciphers for streaming replication?

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> On Aug 26, 2025, at 5:35 AM, xx Z <xxz030811@gmail.com> wrote:
>
> 
> Thanks for your suggestion.
> But I still want to know why we can't set "ssl_ciphers" on the client side.
> This is still considered a security issue in some cases, and PostgreSQL has mature capabilities on the master side to implement this functionality.
>
> Greetings,
> Yunfei Zhou
>

What is your attack/exposure scenario?