How long does propagation of newly registered private name servers typically take?

Question

I have an account with Hostgator, and have registered private name servers (ns1.mydomain.com and ns2.mydomain.com). How long should I expect to wait for those changes to take place? Should my website be unavailable during that time?

Solution 1

Typically no, most major registrars will implement NS updates very quickly (minutes, or just a few hours). What remains is the TTL (time to live) value set on records served by your existing name servers that resolve your domain to its IP.

The typical cache period is 4 hours, however ISP's are free to ignore that, and continue to serve the old IP sometimes up to 72 hours (in most cases). Effectively, some of your users will not realize that you switched until their ISP clears their resolver cache for your domain. I've tried flooring the TTL value on all A records and CNAMES weeks before changing without any kind of positive effect worth reporting.

When doing a switch, refrain from posting new content for at least 72 hours. Additionally, don't do a switch within 72 hours of posting new content, if at all avoidable.

Then again, it really depends on where your users live. Most US ISP's refresh (at least) once every 48 hours. While traveling around Asia, I've seen that process take up to two weeks (but we have to consider horribly configured proxies here).

Depending on your reach, soon after a change your new site and new content will be accessible to most, but some will get a 404. Some might not be able to resolve it at all, it all depends on who hits the ISP name servers (along with what ISP) and when.

Edit (and rather specific to just this question)

Your domain currently points to:

Name Servers:
   ns1.travisnorthcutt.com
   ns2.travisnorthcutt.com

And a dig from public name servers points to:

tpost@tpost-desktop:~$ dig @4.2.2.3 travisnorthcutt.com A

; <<>> DiG 9.6.1-P2 <<>> @4.2.2.3 travisnorthcutt.com A
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37231
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;travisnorthcutt.com.           IN      A

;; ANSWER SECTION:
travisnorthcutt.com.    14400   IN      A       174.122.19.154

;; Query time: 334 msec
;; SERVER: 4.2.2.3#53(4.2.2.3)
;; WHEN: Thu Aug  5 01:56:48 2010
;; MSG SIZE  rcvd: 53

Public NS's (maintained by Level3) are, in order:

4.2.2.1
4.2.2.2
4.2.2.3

And they obey the TTL's you set, at least in my experience. Please disregard the query times, I'm digging from across the globe while using TCP over carrier pigeon.

Solution 2

As a practical matter, I like using What's My DNS, an online tool that samples a number of DNS servers across the planet which will give some idea who's got what, where. It's a great way to get a kind of an answer to the question "has my DNS propagated?"

Comments

[Admin]

Hey dude we're facing exactly the same issue as you did about two years ago. Most places seem to resolve our website correctly, but a few don't. In fact the Public Domains 4.2.2.4, 4.2.2.3 and 4.2.2.1 dont resolve it while 4.2.2.2, 4.2.2.3 and 4.2.2.6 do. We need some help here. Just wanted to ask you if your thing finally got sorted or not?

[zdan]

@KashyapM yes, it finally got sorted. It's been so long I have no idea what happened, but from reading my comments on the accepted answer, it sounds like there was an issue with Hostgator.

[zdan]

Is it strange that I don't even get a 404, just a "oops, chrome (et al) could not find mydomain.com"?

[nedruod]

@tnorthcutt can you post the domain so we can dig it and see what's up?

[zdan]

sure, it's travisnorthcutt.com. I'm also speaking with hostgator's tech support right now - seems as though there is something setup wrong.

[zdan]

thanks for the help - got the issue fixed with help from Hostgator, unfortunately my ISP still has the old DNS cached, so I can't access the domain. Hopefully they'll refresh soon.

[nedruod]

@tnorthcutt Give it ~4 hours.

[Andy]

@Tim - you say 'ISPs are free to ignore that'. Do you know if the relevant RFCs explicitly allow that, or if it's more a case that lots of people ignore it, so that's reality?

[nedruod]

@Andy - Good point to clarify. ISP's should not cache anything longer than the TTL specifies, however, many do in practice.

[Andy]

@Tim - Cheers for that.

[Xster]

could there possibly be a difference in propagation speed for the same domain for http and https?

[Sandeep Bhaskar]

The negative TTL (SOA Minimum) may impact things too...

[Sandeep Bhaskar]

@Xster DNS does not care about HTTP/HTTPS, so these are unrelated.