Update: our Internet service was restored a few minutes ago. Service is running normally now.
The ISP that provides connectivity to our servers is currently totally down. Yes, the entire multi-state ISP, affecting many cities and businesses. The outage began a couple of hours ago. They don't know the cause, nor how long it will take to restore service. My own investigation suggests that the problem is at their peering point with the outside world, not anywhere local to here. Needless to say we will be changing ISP as soon as we can. Apologies to our users. Service will be restored as soon as our ISP gets their act together.