ssl_choose_client_version:unsupported protocol

That does suggest to me that the newest protocol version supported by the server is older than the oldest protocol permitted by the upgraded client. Given that your working client shows a negotiated TLSv1.1 that's probably the highest/newest supported by the server.

Very likely. The LDAP server is ancient, the last update must have been in 2011. Replacement is planned, but for now, we have to work with that old installation.

check the MinProtocol setting in the openssl config of your upgraded machine. You may have to configure it downwards towards TLSv1.1 to permit the connection.

Following https://askubuntu.com/questions/1233186/ubuntu-20-04-how-to-set-lower-ssl-security-level, I modified the openssl configuration to allow TLS v1.1. openssl sclient is now able to connect.

Perl still gets the same old error:

SSL connect attempt failed error:14161044:SSL routines:state_machine:internal error

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

In reply to Re^4: Internal SSL error after Ubuntu update by afoken
in thread Internal SSL error after Ubuntu update by afoken

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.