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The push is fast. Telling people to wait for propagation is incorrect. Also, this isn’t a “nonspecialist misunderstanding”. Very technical people screw this up

The push is fast. Telling people to wait for propagation is incorrect. Also, this isn’t a “nonspecialist misunderstanding”. Very technical people screw this up all of the time. > This latter behaviour is where the term really comes from, the cache-expiry part that causes longer wait times for changes to be globally effective is just kinda grandfathered in under the DNS vernacular “propagate”. Nice job repeating the article. Everything you said is called out in the article but with useful details so people can learn to not think updating A records requires “propagation delay” to start working.

hug 2y ago
So what’s the one-word term for “cache expiry across multiple resolvers that handle caching differently, up to and including resolvers having more than one layer of cache due to forwarding”? This isn’t a gotcha question: I know “propagation” isn’t a technically accurate word, but I’m sure not going to say that sentence when talking about it. I would usually just say “after TTL expiry” to tech colleagues, but that doesn’t work for less technical conversations — saying “the change will take up to 24 hours to propagate” works better for explanations to C-level types.
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inopinatus 2y ago
I’m really repeating my own critique from when it was first published (https://news.ycombinator.com/item?id=29466513 https://news.ycombinator.com/item?id=29466513). Despite being revised to at least mention some more of the mechanics, it’s still somewhat half-baked by omitting any discussion of zones, one of the most significant units of data in the whole system. Moreover, the push is not always fast. There are plenty of 2ary systems in the world that will ignore the notification and only recheck serial after SOA refresh intervals, and others that will queue it for batch update later. Assuming everything works instantly is a tech sector conceit.

hug 2y ago

So what’s the one-word term for “cache expiry across multiple resolvers that handle caching differently, up to and including resolvers having more than one layer of cache due to forwarding”? This isn’t a gotcha question: I know “propagation” isn’t a technically accurate word, but I’m sure not going to say that sentence when talking about it. I would usually just say “after TTL expiry” to tech colleagues, but that doesn’t work for less technical conversations — saying “the change will take up to 24 hours to propagate” works better for explanations to C-level types.

deleted 2y ago
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inopinatus 2y ago

I’m really repeating my own critique from when it was first published (https://news.ycombinator.com/item?id=29466513 https://news.ycombinator.com/item?id=29466513). Despite being revised to at least mention some more of the mechanics, it’s still somewhat half-baked by omitting any discussion of zones, one of the most significant units of data in the whole system. Moreover, the push is not always fast. There are plenty of 2ary systems in the world that will ignore the notification and only recheck serial after SOA refresh intervals, and others that will queue it for batch update later. Assuming everything works instantly is a tech sector conceit.