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Comment by walrus01 | Hacker News Reader

Header in the article:

> DNS is pull, not push

Except for when it is.... If you increment the serial number of a zonefile on your authoritative ns1 and reload the zone, it will push it to any slaves that are configured and set as authoritative for the zone. Very standard IXFR config.

If we are referring to third parties' caching recursive resolvers updating a zone, then yes, it absolutely is pull not push.

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> it will push it to any slaves that are configured

But "it" here doesn't include every DNS server, right? Because, e.g., djbdns definitely doesn't do any pushing when you rebuild the database. And PowerDNS has "native replication" mode where there's no pushing done by the server on changes.

Article specifically addresses this, and "pull, not push" is specifically talking about clients querying resolvers, not zone transfers. No need for the pedantry this time.

This begs the question though: Did her colleague truly believe that a client keeps a record of all DNS records for the entire internet? This is the unspoken result of a belief that DNS is push vs pull.

Otherwise, this is just a simple misunderstanding about which systems are clients in the relationship, which I suppose is less fun to write a blog about.

This is described in section "okay, DNS records actually do “propagate”."

To be fair, your ns secondaries usually does pull the zone (axfr) or zone changes (ixfr) from the primary - the zone reload just sends a notify to trigger it.

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