Addicted to security, my preference goes to monitoring of infrastructures, reporting and incidents handling. Today, networks are a business critical element in companies whatever, their business and size. I like this citation:
“There are three kinds of death in this world. There’s heart death, there’s brain death, and there’s being off the network.”
Hubble, well-known as the NASA space telescope, is also a project from the Washington University (They also maintain the Pine MUA, my favourite one!).
Hubble monitors the Internet in real time about reachability of AS (autonomous systems) and prefixes. As already explained in a previous post, Internet is not bulletproof against network unreachability. Network outages are a threat caused by human errors (remember the Youtube hijacking, hardware failure (the major power failure at LCL a few days ago) or any natural cause like a the Mediteranean sea.
If you can’t reach some part of the Internet, have a look at the Hubble interface. Maybe your destination network will be marked as unreachable. Linked to Google Maps, you can “view” the current black holes on the world map.
If you need to investigate deeper, I recommend you the Routing Information Service maintained by the RIPE. It will give you much more information extracted from the BGP4 global routing table. Of course, for the purists, there are also a lot of public BGP looking glasses (a good list is here).