On: Amazon goes down; takes S3, Salesforce, Target, an...

[justinsb]

It is DNS. If you put the EC2/S3 address into /etc/hosts, the services work fine. Affecting lots of other big websites as well apparently (target, salesforce) because they all outsource to UltraDNS

[shaddi → justinsb]

NANOG chatter confirming it is an issue with UltraDNS. Seems to be west coast related.

EDIT: Potentially a DOS attack. From NANOG: "We have some DNS providing type customers (not UltraDNS) receiving a few million packets/sec of UDP/53 DoS traffic, starting at about the same time as the UltraDNS problems. No clue if it's related, but it certainly sounds suspicious. :)"

[aristus → justinsb]

I'm very surprised that they rely on a single vendor. But I guess DNS is one of those things you don't think about until it fails.

[metachor → aristus]

The point of using UltraDNS is that it they provide fast "real-time" failover of DNS routing. This is used, for example, for fault tolerance where the IP address responding to a domain name might change due to failure scenarios or load balancing (where a different server is now primary responder to the domain name, maybe located in a different data center or country). Infrastructure-wise, UltraDNS is kind of like the Akami of DNS, instead of content distribution.