rname.</p>

</dd>
</dl>

<p>SSL_CTX_set_tlsext_servername_arg() sets a context-specific argument to be passed into the callback (via the <b>arg</b> parameter) for this <b>SSL_CTX</b>.</p>

<p>The behaviour of SSL_get_servername() depends on a number of different factors. In particular note that in TLSv1.3 the servername is negotiated in every handshake. In TLSv1.2 the servername is only negotiated on initial handshakes and not on resumption handshakes.</p>

<dl>

<dt id="On-the-client-before-the-handshake">