We have routing problems to some authoritative DNS services hosted by Edgecast, this is causing some DNS lookups to fail. Example domains that are intermittently failing are flightaware.com, expertflyer.com, lenovo.com, postoffice.co.uk, norwegian.com, twimg.com and some others. We have spoken to Edgecast NOC (after not hearing back from our emails to them) and are sending them further details.
We have spoken to Edgecast again, and they are looking in to this.
We've turned off one of our peerings with Edgecast, and note that the DNS resolution issues are looking somewhat better with this off for the moment from our tests.
Investigations from both sides continue as to why it's being broken.
We have worked around the problem temporarily and DNS is looking to be working ok again. We will investigate further though.
Edgecast have replied saying: "Thank you for the additional information. We are noticing some errors on a couple of our backbone links in one of our London PoP which is where the peering session located. We're currently working with our teams to get these links removed from production. Once this is done, we'll provide an update. "
Edgecast said they saw an issue, but we also found if we take down our peering to them over one of our LINX ports that the problem goes away. We're needing to do a bit more investigation to find out why, but since 6pm-ish routing and DNS lookups to Edgecast is working.