If it's really important to you to offer it to your customers, what we've
done is export the usernames to a file and setup a tacacs daemon especially
to run iPass. It's not that hard to manage and is probably a better
solution because it can stop abuse (a user on our system has to register to
use iPass).
As for accepting iPass, it is up to iPass who they use and they are fairly
picky.
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