How do we know Libya blocked internet traffic? A New Hampshire company continuously tests for internet connectivity:
Update 00:00 UTC Friday 4 Mar 2011
After a quiet week, we received reports tonight that Libyans in Tripoli were suddenly unable to use various Internet communications utilities. Examining the BGP routing table, we saw nothing unusual --- all Libyan routes up and stable.
But our traceroutes tell a different story (no responses from Libyan hosts). All of the Libyan-hosted government websites we tested (i.e., the ones that are actually hosted in Libya, and not elsewhere) were unreachable.
Google's Transparency Report seems to confirm that their Libyan query traffic has fallen to zero as well (click for latest):
The Youtube plot is interesting, suggesting that Google's Youtube traffic from Libya has grown steadily all week. Tonight, however, we suspect that someone has turned off the tap on the Libyan Internet again, this time leaving the routes in place.