Hacker News Reader

Comment by SoftwareMaven | Hacker News Reader

Don't use Google's DNS or Open DNS. That screws with the CDN endpoint you are given and drastically hurts performance.

Holy cow-- I never thought about this. Thank you so much for mentioning because it might explain our sometimes weak streaming performance for different sites.

Would that likely be a general problem with CDN's or is it specific to just Netflix?

Probably a general problem. They (of course, depends on the network) use the DNS system to determine "where" you are to provide a node closer to you. However, you probably will only notice it on things like video where latency can make such a large difference.

I suspect the best way to tell is to run some tests. Shouldn't be that hard to do.

(though, I wonder if youtube suffers when google dns is used. I could see arguments both ways)

While that's generally true for basic CDN backed services like image fills from akamai, DNS geolocation isn't the norm for more complex applications. Netflix specifically doesn't use dns to push you to a specific pop, you first talk to a set of central authentication/drm servers who in addition to giving you your ticket/key also direct you to the video CDN POP they choose for you. The fact that Apple TV made the news because their service was/is broken by anycast DNS servers is just a case of bad engineering and not the industry norm.

And yet when I switched from OpenDNS to my ISP's DNS, I consistently went from marginal quality to almost always HD.

If that's so, what do you do if your ISP's DNS is terrible? Try to find a better one that's still geographically close?

I have a device that I use exclusively for streaming, so I've set it up to use my ISP's DNS. My DHCP server is set to give out OpenDNS' address, so everything else gets good DNS service and my streaming doesn't get hit.

Alternatively, you could probably write a script to bounce back and forth. It would be pretty trivial in Linux; I'm not sure how it would work with OS X (ironically, my OS of choice :) or Windows.

Cache.

http://www.thekelleys.org.uk/dnsmasq/doc.html

Reply on news.ycombinator.com