3 ms·

Performance for Google or Cloudflare isn't going to be better. Where do you get that idea? Do you think all DNS simply lives in their caches? "your ISPs can't

Performance for Google or Cloudflare isn't going to be better. Where do you get that idea? Do you think all DNS simply lives in their caches? "your ISPs can't see what you are doing". If they're analyzing traffic, they can, and if they're doing that, they can see to whom I'm connecting, anyway. But you say nothing about why we should trust Google or Cloudflare. I trust my ISP to be big and dumb. I trust Goole and Cloudflare to want to make money.

icedchai 8y ago
Yes. Performance of Google / Cloudflare DNS will be better simply because so many other people are using them: any common DNS query result will probably already be cached... FYI I run my own DNS server anyway.
- zAy0LfpBZLC8mAC 8y ago
  But what is common for you will usually be cached already in your own server as well, so most requests will still be cache hits--and all those hits avoid the ~ 20 to 100 ms round trip to the internet. Take news.ycombinator.com, for example: The A record has a TTL of 300 seconds. So, after the first visit, which probably will take a bit longer than asking Google/CF, for every request in the next five minutes, you will have a reduced lookup latency. Then, after five minutes, the next lookup will go out to the authoritative server. But mind you that the NS records for ycombinator.com have a TTL of two days, so those are still cached, and the refresh is indeed a single request to the authoritative server--which more often than not takes about as long as a cache hit from the recursive Google/CF resolvers (it's also one round trip to the internet ...). And then, there is stuff like BIND's prefetch mechanism which will start the refresh of an expiring record when it sees a query for that record shortly before its expiry: That query is answered immediately from the cache, and a refresh is started in the background, so that the refreshed record should arrive in the cache before the old version expires ... thus completely eliminating the lookup latency for often-used records. Though you might need to tune it to trigger earlier for your personal use than in the default configuration ...
  - icedchai 8y ago
    True, true. I did not realize BIND had prefetch now. My internal nameserver was running an older bind (from Debian jessie?) I just upgraded to 9.10...
scrollaway 8y ago
Google has spiders that crawl the entire web. Cloudflare RUNS DNS for a bunch of the web. Yes, a lot of DNS does live in their cache, quite literally.
- deleted 8y ago
  [deleted]

icedchai 8y ago

Yes. Performance of Google / Cloudflare DNS will be better simply because so many other people are using them: any common DNS query result will probably already be cached... FYI I run my own DNS server anyway.

zAy0LfpBZLC8mAC 8y ago
But what is common for you will usually be cached already in your own server as well, so most requests will still be cache hits--and all those hits avoid the ~ 20 to 100 ms round trip to the internet. Take news.ycombinator.com, for example: The A record has a TTL of 300 seconds. So, after the first visit, which probably will take a bit longer than asking Google/CF, for every request in the next five minutes, you will have a reduced lookup latency. Then, after five minutes, the next lookup will go out to the authoritative server. But mind you that the NS records for ycombinator.com have a TTL of two days, so those are still cached, and the refresh is indeed a single request to the authoritative server--which more often than not takes about as long as a cache hit from the recursive Google/CF resolvers (it's also one round trip to the internet ...). And then, there is stuff like BIND's prefetch mechanism which will start the refresh of an expiring record when it sees a query for that record shortly before its expiry: That query is answered immediately from the cache, and a refresh is started in the background, so that the refreshed record should arrive in the cache before the old version expires ... thus completely eliminating the lookup latency for often-used records. Though you might need to tune it to trigger earlier for your personal use than in the default configuration ...
- icedchai 8y ago
  True, true. I did not realize BIND had prefetch now. My internal nameserver was running an older bind (from Debian jessie?) I just upgraded to 9.10...

scrollaway 8y ago

Google has spiders that crawl the entire web. Cloudflare RUNS DNS for a bunch of the web. Yes, a lot of DNS does live in their cache, quite literally.

deleted 8y ago
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