Some sort of DNS issue? Maybe a botched change pushed out network wide? Surely if it was a change pushed out it would be rolled back by now?
Edit: On second thought, if they've got no network & no out-of-band - it may take a while... they may need to physically visit each site to re-install the backed-up version!
Edit: On second thought, if they've got no network & no out-of-band - it may take a while... they may need to physically visit each site to re-install the backed-up version!