4 ms·

Yeah, uproar around prices and speeds and stuff like that. Nothing like screwing with third-party DNS requests.

wizzwizz4 5y ago
Actually, I have heard that claim more than once, about various providers (up to, and including, “when I changed my DNS settings and the traffic slowed down, the tech got me to change them back, and the traffic sped up”). It's less common, I think, because more people know how to check their speed than change their DNS.
- jaywalk 5y ago
  The only way I can think of that working is if the provider is intercepting DNS requests for popular speed tests to redirect to an internally-hosted version that would be faster. Otherwise, I can't think of any realistic way DNS settings can affect actual throughput.
  - wizzwizz4 5y ago
    If the ISP is checking for DNS lookup of speed test websites, then allocating higher bandwidth to the connection for a brief period of time? Or, somehow more cynically, the ISP makes money from selling the data collected from DNS, so punishes people who use a different DNS provider. (DNS is plaintext-by-default, so I don't quite see how this would work, but it's possible.) Or perhaps the system uses DNS lookups as a proxy for “is a human browsing the web”; if there aren't enough, it's clearly some kind of automated computer program that doesn't deserve internet access.
    - jaywalk 5y ago
      Your first example would be dead simple to detect and take advantage of to get those boosted speeds all the time. Your other two examples are a bit wild.
      - wizzwizz4 5y ago
        The first example is a real-life example. The other two are speculative, because I've heard a case where it wasn't the first example.
  - tialaramex 5y ago
    So, suppose I'm Huge Video Streaming Corp X, and I get a DNS request asking me for the address of my servers. Well I have over a thousand servers around the globe, which one do you need? Any of them would work, but you likely want the fast nearby one, right? So I can try to guess based on the IP address the query came from... I know the best answer for a Comcast DNS server in New York is the server I physically installed in a New York Comcast rack, but when a public DNS server asks me from Paris, maybe I suggest a London server, 'cos that's pretty close to Paris, shame that New York isn't. EDNS Client Subnet is a feature that lets a DNS server say OK, I'm asking on behalf of somebody from 10.20.30/24 and so my system can do the same trick with ECS. But doing this unwinds most of the privacy benefit of using a public service, so several famous public DNS servers explicitly do not use ECS. Obviously the cheap bulk host used for some Single Serving site like "Is pizza rat mayor of New York yet?" isn't affected, that is only one server and it is wherever it is, but somebody like Netflix absolutely is affected by this because they have their machines close to the customers to deliver better performance and if they don't know where the customer is that inteferes. QUIC has an optional feature called Connection Migration to help improve this, the remote server is like "Um, now that you're connected to www.example.com here in Glasgow, Scotland, I notice your IP address is from Tokyo, Japan, and this is just a suggestion, but maybe talk to my identical twin also named www.example.com in Tokyo, Japan for better performance? Here is the IP address to try"
    - jaywalk 5y ago
      That's not what I meant by "actual throughput." The fact that a download is slower from a server halfway around the world versus one in the same datacenter where my ISP has a peering agreement near me isn't because my connection slows down when I'm hitting the far away server.
    - tk75x 5y ago
      This explanation makes a lot of sense. It also has a slight feeling of Hanlon's Razor, although there isn't necessarily incompetence involved (unless you count the technology's inability to find the absolute fastest/closest server [for whatever reason] as incompetence).

Actually, I have heard that claim more than once, about various providers (up to, and including, “when I changed my DNS settings and the traffic slowed down, the tech got me to change them back, and the traffic sped up”). It's less common, I think, because more people know how to check their speed than change their DNS.

jaywalk 5y ago
The only way I can think of that working is if the provider is intercepting DNS requests for popular speed tests to redirect to an internally-hosted version that would be faster. Otherwise, I can't think of any realistic way DNS settings can affect actual throughput.
- wizzwizz4 5y ago
  If the ISP is checking for DNS lookup of speed test websites, then allocating higher bandwidth to the connection for a brief period of time? Or, somehow more cynically, the ISP makes money from selling the data collected from DNS, so punishes people who use a different DNS provider. (DNS is plaintext-by-default, so I don't quite see how this would work, but it's possible.) Or perhaps the system uses DNS lookups as a proxy for “is a human browsing the web”; if there aren't enough, it's clearly some kind of automated computer program that doesn't deserve internet access.
  - jaywalk 5y ago
    Your first example would be dead simple to detect and take advantage of to get those boosted speeds all the time. Your other two examples are a bit wild.
    - wizzwizz4 5y ago
      The first example is a real-life example. The other two are speculative, because I've heard a case where it wasn't the first example.
- tialaramex 5y ago
  So, suppose I'm Huge Video Streaming Corp X, and I get a DNS request asking me for the address of my servers. Well I have over a thousand servers around the globe, which one do you need? Any of them would work, but you likely want the fast nearby one, right? So I can try to guess based on the IP address the query came from... I know the best answer for a Comcast DNS server in New York is the server I physically installed in a New York Comcast rack, but when a public DNS server asks me from Paris, maybe I suggest a London server, 'cos that's pretty close to Paris, shame that New York isn't. EDNS Client Subnet is a feature that lets a DNS server say OK, I'm asking on behalf of somebody from 10.20.30/24 and so my system can do the same trick with ECS. But doing this unwinds most of the privacy benefit of using a public service, so several famous public DNS servers explicitly do not use ECS. Obviously the cheap bulk host used for some Single Serving site like "Is pizza rat mayor of New York yet?" isn't affected, that is only one server and it is wherever it is, but somebody like Netflix absolutely is affected by this because they have their machines close to the customers to deliver better performance and if they don't know where the customer is that inteferes. QUIC has an optional feature called Connection Migration to help improve this, the remote server is like "Um, now that you're connected to www.example.com here in Glasgow, Scotland, I notice your IP address is from Tokyo, Japan, and this is just a suggestion, but maybe talk to my identical twin also named www.example.com in Tokyo, Japan for better performance? Here is the IP address to try"
  - jaywalk 5y ago
    That's not what I meant by "actual throughput." The fact that a download is slower from a server halfway around the world versus one in the same datacenter where my ISP has a peering agreement near me isn't because my connection slows down when I'm hitting the far away server.
  - tk75x 5y ago
    This explanation makes a lot of sense. It also has a slight feeling of Hanlon's Razor, although there isn't necessarily incompetence involved (unless you count the technology's inability to find the absolute fastest/closest server [for whatever reason] as incompetence).