I have been a Netflix subscriber for a couple years now but really haven’t been using it much I can’t find much on it that I’m interested in watching.
One issue that cropped up several months ago for me was I was no longer able to stream in HD. No matter what various “internet speed tests” reported Netflix always resorted to SD streams. Most recently speedtest.net reported my pipe as having 27Mbps of throughput.
Since I don’t use it that much I didn’t care too much, and just stopped streaming stuff for a while (I stream to my Tivo Series 3). Today I decided to try to dig a little deeper, there wasn’t much help on the Netflix site, and calling them was not too helpful they just suggested I ask my ISP to perform a longer running test to see if the connection was stable and reboot the modem.
Before trying that though (well I did reboot the modem to no avail), I decided to run tcpdump on my firewall and see where Tivo was sending it’s packets, and then use something like mtr to measure latency to that destination.
I noticed within seconds my Tivo was sending packets to a Lime Light node in Miami, not exactly next door to the Seattle area where I am at. Sure enough the Miami node is 16 hops away and right at around 100 milliseconds of latency.
Why was this going there?! Well it has to be related to DNS, as I’m sure at some point I started forwarding all of my DNS packets to my personal virtual server(same one that runs this site) which is run out of Miami. So Limelight must be using BGP Anycast for their DNS which is common among other global DNS providers, but it ended up biting me in the ass.
I originally was routing all of my DNS traffic over to my personal system (across a VPN no less) because I don’t know what kind of crap might go on on my consumer broadband connection with Comcast (at one point I remember some ISPs doing funky things with negative DNS responses for example). Probably nothing but I thought what the hell, why not (the VPN is already in place, and I’m already running local caching name servers as well as a remote caching name server (not the same name server that hosts my domains externally those are different), it’s 1 line in a config file to forward the traffic).
Well now I know why not.. at some point I may invest the time to try to figure out how to send Netfix DNS traffic to a local site and the rest go to my server, but for now I’m not going to spend the time.
Once I disabled forwarding of DNS packets to my remote system, and restarted my name server to flush the cache, Tivo started using a Seattle Limelight node, and the hops dropped to 10, and latency dropped to around 15 milliseconds, HD streaming was now possible once again.
It’s also gotten me wondering how many other services that I use that may of been impacted by routing my DNS traffic 3,000 miles away. Though other than Netflix I have not noticed any ill effects, though the amount of data that traverses my connection is pretty minimal (62GB of data since the beginning of March until June 15th according to Comcast, that includes a pretty big backup I did of my personal server to my local network a few weeks ago).
Given that DNS round-trip time is in the critical path for most Internet activity, including web pages, does it make sense to run a DNS server so far away? Have you considered using Google’s anycasted 8.8.8.8 DNS server?
Comment by Fazal Majid — June 15, 2011 @ 1:51 pm
Yeah I’m sure it’s more optimal to run something closer, my server just happens to live in Miami. I’ve been running my own DNS (local caching as well as authoritative) for so many years it’s just been habit to continue doing that instead of using external like Comcast or Google or something. Old habits die (very) hard 🙂
thanks for the comment!!
Comment by Nate — June 15, 2011 @ 4:12 pm
[…] that trouble tracking down why my Netflix HD streaming was not working for nothing? I guess so. Netflix sent me an email a short time ago said they were […]
Pingback by Netflix jacks up rates – I cancelled « TechOpsGuys.com — July 12, 2011 @ 2:59 pm
I understood very little of your article but I am unable to stream netflix in HD despite tests showing network speeds of up to 10mbps. I can watch movies on Vudu in 1080p quality with no buffering issues but when I choose an HD movie from netflix to watch it displays sd / low this varies to sd / med and sd / high but have yet to see anything in true hd.
Comment by jesse — January 8, 2013 @ 8:42 pm
also I should mention I tried changing dns settings to google’s 8888 etc. to no avail.
Comment by jesse — January 8, 2013 @ 8:43 pm
For me my specific situation was the DNS I was using was located 3,000 miles away from me. So Netflix was sending me to a server that was too far away to stream to me fast enough to support HD (they determine what server to send you to based on where your DNS queries go to).
Troubleshooting such a setup can require somewhat advanced technical knowledge – for me I was looking at the raw network data to see what server netflix was sending me to (I was using a Tivo to stream), which is how I determined the server they were sending me to was on the east coast of the US, and I was in Seattle (not a good combination for streaming media). Have you tried another device, maybe the issue is specific to the Netflix software on whatever device you are using.
Comment by Nate — January 8, 2013 @ 8:49 pm