The roadwarrior <b>carol</b> sets up a connection to gateway <b>moon</b>.
At the outset the gateway authenticates itself to the client by sending
an IKEv2 <b>digital signature</b> accompanied by an X.509 certificate.
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Next <b>carol</b> uses the <i>MD5</i> (<b>EAP-MD5</b>) method of the
<i>Extensible Authentication Protocol</i> to authenticate herself.