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I have a domain for which I updated the nameservers to point to my new server not long (~ 1 hour) ago:

The WHOIS report tells me it's been updated:
http://www.dnsstuff.com/tools/whois/?ip=ablazex.com&cache=off

Why is that when I try to access the site or even ping it, it still resolves to the old server?

NullUser
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6 Answers6

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Unless you have set a nonstandard "time to live" on your old DNS server, you must wait a considerable amount of time (typically 1-7 days) for remote users' cached DNS records to expire. This ordinarily can be prevented by setting the TTL to something very short (e.g. 5 minutes); however, for obvious reasons, the TTL change should have been made at least a week in advance of the server change, and it cannot be done retroactively. At least you'll know what to do differently next time.

Suggestions:

  1. If you are serving entirely static content, you should consider the option of simply keeping both servers up for a few days.

  2. If the server in question is a web server, you may be able to configure your old site to redirect visitors to the new site during the transition. Configure an entirely new "A" record as a subdomain (e.g. "new.example.com") pointing to your new site's IP address. Then, on your old server, set up an HTTP refresh header (or the equivalent meta tag) redirecting all clients to the new site.

[edit] This answer is based upon the following assumptions:

  1. We presume that the probable cause is an A record that has been cached by various client machines, ISP nameservers, etc. We do not know the TTL for the stale A record associated with @NullUserException's domain. In my personal experience, web hosting companies seem to favor 48 hours as a default TTL, but others here have reported seeing other default values. We also find it highly unlikely that anyone has ever changed the default.

  2. We assume that @NullUserException wants everyone (not just himself) to be able to access the site at the new location; therefore, potential workarounds affecting only the local computer (e.g. flushing the local DNS cache or editing the local hosts file) are not offered.

  3. "DNS records" refers to DNS records in general, not any specific type of DNS record.

Skyhawk
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    Finding the name servers and accessing a site at that domain are two different things. It appears the OP's problem is accessing a site at that domain. While the problem may in fact be with cached name server records as you've stated, it could just as well be with a cached A record or a misconfigured A or CNAME record. – joeqwerty Aug 18 '10 at 23:02
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    What I wrote above was based on what I would consider to be the most common problem with these first-time cut-over scenarios: a cached A record with a typical default TTL of 48 hours. Of course, you are absolutely welcome to suggest other potential causes. – Skyhawk Aug 18 '10 at 23:24
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    @Miles: I follow you. My answer and my comment to your answer was based on the fact that his access and ping were going to the old server, which suggests that he's trying to access his web site, which suggests an A or CNAME record problem. If it were an NS record problem then his tests wouldn't have resolved to anything, the old or the new server. Of course I meant no offense in my answer or comments. – joeqwerty Aug 19 '10 at 01:32
  • @joeqwerty: When I said "DNS records" above, I meant DNS records in general -- including A records, CNAME records, MX records, etc. I am a bit confused by your interpretation, because I never said anything specific about NS records (or any other particular *type* of DNS record) in my original answer. My logic: no matter which type of DNS record is being cached, it is likely subject to a 48-hour default TTL. – Skyhawk Aug 19 '10 at 02:32
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    @Miles: My apologies. In your answer you made mention of his DNS server and I took that to mean that you were referring specifically to his NS records and not A or CNAME records (or any other record for that matter). Sorry for any confusion I may have caused. – joeqwerty Aug 19 '10 at 02:51
  • I see 24 hours and 7 days often but have not yet seen a default of 48 hours. – John Gardeniers Aug 19 '10 at 02:53
  • I see 48 hours more commonly for NS records and lower TTL's for all other records. – joeqwerty Aug 19 '10 at 02:59
  • @Joe, no worries, I should have been clearer! @John & Joe: the 5 web hosting companies that I personally have done business with since the mid-1990s all have used 48 hours as a blanket default, but I am absolutely willing to believe that other defaults exist. I have edited this answer to incorporate your feedback. – Skyhawk Aug 19 '10 at 15:37
  • @Miles: Thanks for the feedback and +1 for your answer. – joeqwerty Aug 19 '10 at 23:27
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When you say that when you try to access the site or ping it it's going to the old server, can you be more specific? Are you trying to go to www.domain_name.com? If so, what is the A or CNAME record for www pointing to? Start at the top of the chain: run nslookup (or dig) and query for the name servers for the domain. Take those results and query those name servers for the A or CNAME record for the site. What do the results tell you?

joeqwerty
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Your problem will probably be solved within 48h, but in the meantime, if you need your pc to translate ablazex.com to another IP then the one your DNS comes up with, you can add the IP in your host file. In windows it's at c:/Windows/System32/Drivers/Etc/Hosts, you can edit it with notepad and add the following line: 

xxx.xxx.xxx.xxx ablazex.com

Where xxx.xxx.xxx.xxx is the IP you want ablazex.com to point to. Sometimes the only problem is your PC's DNS cache. Presuming your using Windows, you can type in a command prompt: 

ipconfig /flushdns

This will flush the dns cache of your PC and maybe solves your problem, be sure to restart your browser after editing the host-file or flushing your DNS cache.

Karst Lok
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  • See my comment to joe's answer. Where did you come up with 48 hours? Did you just pick that number or are you merely propagating the DNS propagation myth? His NS records may have a TTL of 48 hours (which you would only know if you looked it up) but you have no idea what the TTL is for any other DNS records in his DNS zone. As it is, his question is likely an A or CNAME record problem. – joeqwerty Aug 19 '10 at 01:29
  • That's why I said "probably". His problem is not likely a A or CNAME problem, explain to me why DNS propagation is a myth, don't give me crap. – Karst Lok Aug 19 '10 at 07:20
  • I'm not giving you crap. How did you come up with 48 hours? Did you just pick a random number? Did you make an assumption that his DNS records had a TTL of 48 hours? DNS propagation is a myth because DNS records don't propagate. – joeqwerty Aug 19 '10 at 12:03
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The problem is that your internet provider (or internal network's) cached DNS server has not yet been refreshed. You may wish to connect to a proxyserver (search for one on google). Once your external IP is different (as confirmed by checking on cmyip.com), do the following:

Clear your local DNS settings. On Windows, start a command prompt, and type:

ipconfig /flushdns

Re-load your page.

Shailen
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Same thing happened with me but since I was knowing that the TTL should be reduces prior doing server transfer so I did following and it solved my problem.

  1. Go to Old Server DNS Records of your site.
  2. Edit previously existing A record or Create new A record pointing the new server IP. if the new site is domain then A ; DomainName.com; New Server IP if its sub domain then A ; SubDomain.Domain.com; New Server IP
  3. Similarly point the ns records on DNS records of old server to the new IP.
  4. Create same NS records (pointing new server IP) on the new server as well.

This solved my problem.

Alternate Solution: If it is possible that you can instruct the users in person, you can also ask them to execute on cmd "ipconfig /flushdns" and restart all browser of user's computer.

Hope this helps! Thanks

VAIBHAV JAIN
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your DNS change can take up to 48 hours to filter down through all DNS resolvers. This is something that can not be avoided in almost all cases. unless you are very very close the the root. Just sit back and wait, if you can not get to in 24 hours you might want to contact the oporator of the nameservers.

Liam
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    We need to stop saying that "The DNS needs to filter down through all DNS resolvers" or "The DNS will take 48 hours to propagate" because that's not how DNS works. DNS records are cached not propagated. If the host has none of your DNS records in it's resolver cache then it will resolve the new information immediately. If it does have your DNS record in it's resolver cache then that information will persist for the remainder of the TTL. – joeqwerty Aug 19 '10 at 01:26