-Now start your session. To check that PuTTY has set up the port
-forwarding correctly, you can look at the PuTTY Event Log (see
-\k{using-eventlog}). It should say something like this:
+Now start your session and log in. (Port forwarding will not be
+enabled until after you have logged in; otherwise it would be easy
+to perform completely anonymous network attacks, and gain access to
+anyone's virtual private network). To check that PuTTY has set up
+the port forwarding correctly, you can look at the PuTTY Event Log
+(see \k{using-eventlog}). It should say something like this: