 or Next Protocol Negotiation (NPN) extension, respectively. ALPN is the IETF standard and replaces NPN. The <i>val</i> list is a comma-separated list of supported protocol names. The list should contain the most desirable protocols first. Protocol names are printable ASCII strings, for example &quot;http/1.1&quot; or &quot;spdy/3&quot;. The flag <b>-nextprotoneg</b> cannot be specified if <b>-tls1_3</b> is used.</p>

</dd>
<dt id="ktls"><b>-ktls</b></dt>
<dd>

<p>Enable Kernel TLS for sending and receiving