The roadwarriors <b>carol</b> and <b>dave</b> set up a connection to gateway <b>moon</b>.
The authentication is based on Pre-Shared Keys (<b>PSK</b>)
followed by extended authentication (<b>XAUTH</b>) of <b>carol</b> and <b>dave</b>
based on user names and passwords. Next <b>carol</b> and <b>dave</b> request a
<b>virtual IP</b> via the IKE Mode Config protocol by using the <b>leftsourceip=%config</b>
parameter. The virtual IP addresses are registered under the users' XAUTH identity. 
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Upon the successful establishment of the IPsec tunnel, leftfirewall=yes automatically
inserts iptables-based firewall rules that let pass the tunneled traffic.
In order to test both tunnel and firewall, <b>carol</b> and <b>dave</b> ping the client
<b>alice</b> behind the gateway <b>moon</b>.