How to Test New Server's Nameservers?

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JMZ

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Hi everyone, my question is a pretty simple one. I am hoping someone can advise me on how to test some newly setup nameservers, without editing the registration of the nameservers with the domain registrar.

I am working with an existing website with it's own dedicated server, which hasn't been moved over 3 years. For some reason the hosting provider is terminating several servers, ours being one of them. We've been given a replacement server and I am looking to transition over everything as smoothly as possible.

I have setup the new nameservers using two addon IP addresses, just as another employee setup a few years ago and I have configured the DNS exactly as described on several tutorials (and consistent with old server configuration).

Normally if I was just using A records for a website and I wanted to minimize downtime, I would set the domain in my local HOSTS file in C:\Windows\System32\drivers\etc to point to the new server IP so I could get the new server completely setup before changing anything at the registrar.

I've attempted to do the same thing with the new nameservers. I've modified my HOSTS file to point both ns1, ns2 to the new nameserver IP addresses and when I ping ns1.domain.com it echos back the new nameserver IP addresses. However, when I try to load the domain in the browser, or ping the domain it still returns the old server IP address, not the new one.

My question; is this happening because pointing my hosts file at the new nameservers just won't work as a testing method, or does this indicate that I have not actually configured DNS/nameservers on the new server correctly?
 
without editing the registration of the nameservers with the domain registrar.
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I think this is your problem. If you have new nameservers or in fact new ip adresses for your nameservers, you have to edit the registration with the domain registrar, because you need glue records.
The domain name you are looking at then, is not using your hosts file, so can't be seen due to the fact that you won't get the correct answer from your nameservers or the webserver can't present you the correct virtualhost.

So in fact pointing to your hosts file is good for testing A records, but not for testing nameservers.
 
Thank you very much for your reply Richard, I couldn't find any information confirming whether or not testing nameservers in this fashion was possible, very happy to have it cleared up.

To your knowledge; is it possible for me to test this out in some other way before I make the changes to the nameserver registration, or must I just make the changes live and hope for the best?

Just FYI, this is how I setup:

  1. logged into DA as admin
  2. added both new IP addresses in 'IP management' and assigned to "admin"
  3. switched to reseller mode
  4. created both nameservers using new IP addresses in 'nameservers' area
  5. switched back to admin mode
  6. navigated to administrator settings area
  7. set newly created nameserver as ns1, ns2 and added appropriate hostname
  8. saved changes

From everything I've read, it seems all I have left to do is make the changes with the registrar. If you think I've done something there incorrectly, please let me know.
 
My explanation is technically not 100% correct, I made it a bit easyer to understand, but still, you can't use your hosts file to test nameservers.:)

Another way you might use to test a bit is an undelegated DNS test.
On the site you can do a "undelegated domain check" and put in (or change) the ip adresses you use. You will get glue errors, but the check will let you see if the rest is OK. I normally only do that for .nl domains.
But I had a look with Google and found the following for you:
http://www.dma.nl/dnscheck2/?faq=1&test=undelegated

So you can try that. But remember, you will get glue errors and errors that the nameservers are not authoritive for that domain. And you might get some errors that other nameservers were found for the domain (your registrar's nameservers probably).

On the other side, it looks like you did very well.
Ofcourse I presume you have a domain name as admin, to be used for the nameservers.
To be sure, check your DNS settings of the domain and check if there are 2 entry's for either nameserver.
One entry like this:
domain.com. NS ns1.domain.com.
mind the dot at the end, it's necessary.
and an A record like this:
ns1.domain.com. A 217.55.55.55 (example ip adress)

If you got that, you're oke to go and change nameservers at your registrar. If you encounter any problem, feel free to post a reply here or contact me via pm or mail.

Edit: Ohyeah, after changing nameservers at your registrar, it normally takes 4-6 hours before they resolve. On slow DNS updates it can take up to 24 hours (some say up to 48 hours but I never experienced any that long).
 
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Hey Richard.. Well I was able to get the database and all of the content moved over to the new server, but today I have tried to point my nameservers at the registrar to the new IP addresses and within seconds I was unable to access the site. Browser gives error "Error 137 (net::ERR_NAME_RESOLUTION_FAILED): Unknown error.", so I have switched them back.

To respond to what you asked me, yes I did setup the domain first as admin, I forgot to mention that, but that was something I had to do first in order for the domain to be available in the "nameservers" area when in reseller mode. I did verify that this exists in the DNS settings for the domain:

domain.com. NS ns1.domain.com.
ns1.domain.com. A 217.55.55.55

It seems what I have done is right in line with every tutorial I have found and just as you said it should be. I'm really not sure why it is not working.

I have contacted our server company to explain the issue. They suggested that perhaps there was a conflict between the old server's existing DNS and the new server's DNS, however I didn't think that made any sense as the registrar would be pointing to the new one, so the old one shouldn't even be an issue anymore (if this was possible it would be pretty easy to hijack a domain name). After I said this the technician informed me he was passing the issue up to an administrator and I should be contacted in 8 hours.

Regarding your edit, I did assume it would take some time to resolve. However, during the propagation period, I would expect no downtime at all as the old and new nameservers are pointing to clones of the site (so obviously some customers would actually be loading the old server and some would be loading the new server during this time, but the site would still load and domain still ping).

I should also add that when I made the switch I did test the DNS before and after using an online tool and the before was good, but the after was giving a failure error (no information provided at all). I also was able to sucessfully ping ns1.domain.com and received old IP addresses and when pinging after the nameserver update with the registrar, the ping didn't even echo back the new IP, it just failed.

I will post back when I hear from the server company, perhaps there is something wrong with the addon IP addresses being used as the new nameservers. If you do read this in the meantime and think of anything, I would appreciate further input from you.
 
You should update the nameservers at your domain registar so that the glue records are up to date. Also you should change the A records on both your old and new servers so they point to the right ip.
 
Okay so as it turned out, I was doing everything correctly, but the secondary/addon IP addresses weren't properly pointing at our server, something on the server company's end. They gave me two new IP addresses and everything now works perfect.

@chatwizrd I appreciate you taking the time to reply to this thread, but you must not have read the whole situation. The final step was the registrar update, everything else was done, but it didn't work (as it turns out because the IP addressess I was given by my provider were not valid).

Changing A records on the old server would do nothing except put me under an illusion everything was working, when it was not, so I can't understand the reasoning behind this.

Thanks again for your input Richard!
 
Changing A records on the old server would do nothing except put me under an illusion everything was working, when it was not, so I can't understand the reasoning behind this.
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That's quite correct. I don't do that either. However, this can be done to prevent for example new mail arriving at the old server, which could cause users to miss some mail. But in fact it's not necessary.

Regarding your edit, I did assume it would take some time to resolve. However, during the propagation period, I would expect no downtime at all as the old and new nameservers are pointing to clones of the site (so obviously some customers would actually be loading the old server and some would be loading the new server during this time, but the site would still load and domain still ping).
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That is indeed a correct assumption.

Nice to see you found out what was going wrong and was able to fix it.
Regarding to my input, you're very welcome. Glad to be of help!
 
Richard G said:
However, this can be done to prevent for example new mail arriving at the old server, which could cause users to miss some mail. But in fact it's not necessary.
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When we move sites between servers we always move mail again about a day later, to make sure any mail still coming to the old server gets to the new server.

Jeff
 
We mostly have hobby sites on our servers and when sites are transferred, I mostly stop the exim process, so no new mail is able to come in on the old server.

Just out of interest
we always move mail again about a day later
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How do you do that? Do you make an admin backup with only mail selected or do you use another method?
 
Richard G said:
How do you do that? Do you make an admin backup with only mail selected or do you use another method?
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Exactly. I've tested and mail already in the destination inboxes get overwritten, mail moved to other folders (with IMAP) gets duplicated, all indexes appear to be updated, and everything works.

Jeff
 
Great, thank you for the explanation, I'm going to try that next time too, it's eayser (and better for those who don't have a backup-mx) to do it that way.
 
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