<p></p>
<p>Yes, 4.2.8 is a crucial problem part here. With this workaround, we can run into the problem that we force close a session and cannot re-establish the session with the same peer until the other side timeouts/resets the session on their side. I mentioned this problem in comment <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="873019161" data-permission-text="Title is private" data-url="https://github.com/RIOT-OS/RIOT/issues/16422" data-hovercard-type="pull_request" data-hovercard-url="/RIOT-OS/RIOT/pull/16422/hovercard?comment_id=855876182&comment_type=issue_comment" href="https://github.com/RIOT-OS/RIOT/pull/16422#issuecomment-855876182">#16422 (comment)</a>. To be honest, I consider 4.2.8 as a MUST and not a SHOULD for a DTLS stack, especially when used on constrained devices.</p>
<p>But this is and was a problem even without this workaround, since we do not get informed by the API right now if the closing was successful (= ACK from the remote part). In the case closing was unsuccessful, it could make tinyDTLS unusable in the long run without noticing by the application.</p>
<p>This workaround should never stay forever, it's only supposed to be a temporary solution for clients, so they don't become unusable over time if the close_notify is not ACK-ed.</p>

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