Yes you can but this is not one line change. Assuming you have a
single server (not mutliple servers behind a NAT), the easy way is to
replace the register function in controllers/default.py with the
following code:
if t2.logged_in: cache.ram('client:%s' % t2.person_id, lambda:
request.client, 0) ### store client ip in cache
def register():
form=t2.register
(verification=settings.email_verification,sender=settings.email_sender)
if t2.logged_in:
client=cache.ram('client:%s' % t2.person_id, lambda:
request.client, 300) ### retrieve client ip
if client and client!=request.client: ### if no match, force
logout
t2.messages.logged_out="sorry, somebody else is currently
logged in as you"
t2.logout(next='login')
return dict(form=form)