ULL, SNI is not used.</p>

<p>The servername callback should return one of the following values:</p>

<dl>

<dt id="SSL_TLSEXT_ERR_OK">SSL_TLSEXT_ERR_OK</dt>
<dd>

<p>This is used to indicate that the servername requested by the client has been accepted. Typically a server will call SSL_set_SSL_CTX() in the callback to set up a different configuration for the selected servername in this case.</p>

</dd>
<dt id="SSL_TLSEXT_ERR_ALERT_FATAL">SSL_TLSEXT_ERR_ALERT_FATAL</dt>
<dd>

<p>In this case the servername 