Asterisk goes down without adsl connection

Hi,
I have an installation (elastix 2.0 and freepbx 2.7) with some voip trunks configured.
When internet connection goes down, also all internal sip registrations go down.
Can anyone help me?

thanks
Massimo

http://www.freepbx.org/support/documentation/howtos/how-to-install-bind-so-that-sip-extensions-continue-to-work-when-intern

Thanks a lot, I’ll try it