Ironically, this highlights one of the main issues we discuss in the post!
The Twilio Engineering blog is hosted off an external Wordpress site with a single IP that's forwarded from ngnix load balancer pool. Since the load balancers assume that the external service can fail, they won't tied resources blocking access to other parts of the site.
Evan, I just noticed that your service seems to be running on Slicehost, not the AWS colo in Virginia. Is that correct? I got the opposite impression from your post, which seems to imply that Twilio is hosted on AWS, yet managed to weather the storm because of your design decisions.
Ah, I see it now. I just got a POST from one of your servers in the AWS US-West region. Is Twilio also hosted in US-East (the region affected by today's outage), and, if so, would Twilio have stayed up if it hadn't been spread across multiple regions?
dmor, really? It looks like the blog points to AWS, as does your API?
jdyer@aleph:~ [git:master] <ruby-1.9.2>
» host api.twilio.com
api.twilio.com is an alias for public-vip374d1ca4e.prod.twilio.com.
public-vip374d1ca4e.prod.twilio.com is an alias for ec2-174-129-254-101.compute-1.amazonaws.com.
ec2-174-129-254-101.compute-1.amazonaws.com has address 174.129.254.101
----
jdyer@aleph:~ [git:master] <ruby-1.9.2>
» host www.twilio.com
www.twilio.com is an alias for public-vip29c4ab3d.prod.twilio.com.
public-vip29c4ab3d.prod.twilio.com is an alias for ec2-174-129-253-75.compute-1.amazonaws.com.
ec2-174-129-253-75.compute-1.amazonaws.com has address 174.129.253.75
DNS lookups don't tell you anything here. The way a reverse proxy works is that HTTP requests to certain URLs get turned into an HTTP client request by the web server to the 3rd party provider (for caching, URL changing, compressing, terminating SSL, and get around firewalls). You can learn about them here: http://en.wikipedia.org/wiki/Reverse_proxy
True, and I had actually misread dmors' post entirely here; I read the post as stating Twilio's blog was not reliant on AWS in anyway, which would have been a misrepresentation in my mind. However in hindsight this was not the case, and I will certainly admit when I am wrong.
nginx/0.9.2
You really want to make sure your shit works before you go boasting about how well it works. :)
EDIT: seems to be working now :P Interesting article once I got over the irony of it not working.