DNS root server l.root-servers.net has changed its IP address. It used to be 198.32.64.12, it’s now 199.7.83.42.
If you are running Bind, you should edit your root cache file (called root.hint or so) and change.
L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12
to.
L.ROOT-SERVERS.NET. 3600000 A 199.7.83.42
If you are running Dnscache, change 198.32.64.12 to 199.7.83.42 in your dnsroots.globals file.