DNS errors on some machines only

Question

I have a site (growdental.co) that I'm having some extremely frustrating DNS issues with. Basically, the site seems to work fine, until the domain randomly stops resolving the ip. I thought I had isolated the problem, but it keeps happening. Here is what I know

1) I thought it might have been an ISP thing, but I tried on another machine on the same network and it resovled fine....for a few days, then I had the same issue on multiple machines. I have also recently experienced the same problem on the other side of the world, on a different machine

2) I can 'fix' the problem by editing local host file - which I thought was fine because it was my ISP, but now I see it's not, I want to make sure clients can get to this site.

3) The site is hosted on a VPS. No other sites on the VPS have had any problems.

4) I have spoken to hosting company and they say everything is fine on their end

5) I am forcing site into https using .htaccess (if that makes a difference)

Any help on this would be HUGE. I've been pulling my hair out for weeks and no one seems to know what is going on....

Thanks,

Nick

Answer 1

One of your name servers for growdental.co--NS2.DENTAGROW.COM--isn't able to be resolved properly (sometimes?).

 $ host NS2.DENTAGROW.COM
 NS2.DENTAGROW.COM has address 202.130.46.118

 $ host NS2.DENTAGROW.COM
 Host NS2.DENTAGROW.COM not found: 3(NXDOMAIN)
 Host NS2.DENTAGROW.COM not found: 3(NXDOMAIN)

 $ host growdental.co NS2.DENTAGROW.COM
 host: couldn't get address for 'NS2.DENTAGROW.COM': not found

From http://www.kloth.net/services/nslookup.php

 DNS server handling your query: localhost
 DNS server's address:  127.0.0.1#53

 ** server can't find NS2.DENTAGROW.COM: SERVFAIL

Since DENTAGROW.COM's name servers are NS[12].DENTAGROW.COM are you sure the glue record is set up?

Answer 2

ns1.dentagrow.com is configured incorrectly. It is able to resolve itself

host ns1.dentagrow.com ns1.dentagrow.com
Using domain server:
Name: ns1.dentagrow.com
Address: 202.130.46.117#53
Aliases:

ns1.dentagrow.com has address 202.130.46.117

But it can't resolve the other nameserver:

 host ns2.dentagrow.com ns1.dentagrow.com

Returns no answer.

Edit: Sorry, I was confused by the hostnames being almost, but not quite, alike, so I was looking for the wrong domain... ns1.dentagrow.com does resolve growdental.co correctly.

The fix should be to edit the dentagrow.com domain on ns1.dentagrow.com to add the ns2.dentagrow.com host so that ns2.dentagrow.com exists (and being sure to increase the serial# so everyone else knows it has updated).

Answer 3

You have a few errors, check the DNS report:

http://www.dnsvalidation.com/growdental.co

1. Nameserver ns2.dentagrow.com does not responds to queries (NXDOMAIN - no A record)
2. You have 2 stealth nameservers without A records (ns1.growdental.com, ns2.growdental.com )

Solution:

1. Sync nameservers list from your domain configuration with those configured at your registars
2. Ensure yourself that each domain's nameserver has an A record