domain name system - Best Practices in Speeding-up DNS Propagation

I recently changed nameservers and it has been 24 hours since.
Some of my visitors are complaining they are still viewing the old site while some are already seeing the new site. Is there any way to speed-up the DNS propagation without updating the hosts file of each of my visitors?

Are there any best practices when it comes to changing nameservers to minimize this problem?

Answer

DNS records doesn't propagate in the sense that they aren't "pushed" from your server to other resolvers. What actually happens is that when other DNS servers look up your domain, they cache the record for X seconds so that they don't have to do another lookup for subsequent requests. X seconds should be determined by the TTL value on the record when it was retrieved from your name server. If you've already changed the address there's nothing you can do but sit and wait. If you had planned this in advance, you could have lowered the TTL value.

Some larger DNS resolvers cache longer than the TTL, which is a violation of the relevant RFCs (but they don't care). If you can track this issue down to a few name servers, you can email the operators and ask them to invalidate the cache for your zone so that they'll stop using the cached (old) record.

Honestly, though, unless this goes on for an extended period of time, it's probably just as well that you sit tight and wait and plan a better migration for next time, since the damage is already done.