2

I've just noticed some very strange and concerning results when I attempted to do an nslookup for a one of my domain names from one of my hosted virtual servers.

The domain [mydomain].info is resolving as [mydomain].info.com.au and listing 4 IP's that I don't use.

This only happens on one server, and only for this domain and sub-domains (from the testing I've done) .

Things I've tried...

1) "ipconfig /flushdns". No effect.

2) Checked hosts file. Nothing suspicious.

3) I've checked the registry for entries related to the DNSChanger virus, but I can't see anything suspicious.

4) Changed the DNS server for the connected interface. nslookup shows the new DNS server, but the results are the same.

5) Scanned the dnslookup.exe for virus's, but nothing appears. Also if I run a query using this executable from another computer, the results are correct.

I don't know if this means my server is actually compromised, or if possibly my hosting provider is doing something dodgy with outbound dns lookups.

The server is Windows Server 2012

Other than this dns issue the server is working perfectly. I haven't observed any other strange behaviour.

If anyone has any suggestions they would be greatly appreciated. This is a live, production server, hosting a number of client websites, so this is stressing me out quite a bit.

Here is the output, as requested. My apologies, I would prefer to not show the actual domain name, as it is personally identifiable. However I have verified that the domain records are correct.


PS C:\scripts> nslookup [mydomain].info
Server:  google-public-dns-a.google.com
Address:  8.8.8.8

Non-authoritative answer:
Name:    [mydomain].info.com.au
Addresses:  52.3.124.67
          52.201.189.141
          54.85.85.70
          52.5.111.221

PS C:\scripts>

After some more investigation, it appears it is not just my domain. It happens with any .info domain. I've included the nslookup results with debug turned on...

> somedomain123123.info
Server:  google-public-dns-a.google.com
Address:  8.8.8.8

------------
Got answer:
    HEADER:
        opcode = QUERY, id = 74, rcode = NXDOMAIN
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 0,  authority records = 1,  additional = 0

    QUESTIONS:
        somedomain123123.info.hosting24.com.au, type = A, class = IN
    AUTHORITY RECORDS:
    ->  hosting24.com.au
        ttl = 1799 (29 mins 59 secs)
        primary name server = ns1.web24.net.au
        responsible mail addr = dns.web24.net.au
        serial  = 2016060205
        refresh = 7200 (2 hours)
        retry   = 3600 (1 hour)
        expire  = 604800 (7 days)
        default TTL = 3600 (1 hour)

------------
------------
Got answer:
    HEADER:
        opcode = QUERY, id = 75, rcode = NXDOMAIN
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 0,  authority records = 1,  additional = 0

    QUESTIONS:
        somedomain123123.info.hosting24.com.au, type = AAAA, class = IN
    AUTHORITY RECORDS:
    ->  hosting24.com.au
        ttl = 1799 (29 mins 59 secs)
        primary name server = ns1.web24.net.au
        responsible mail addr = dns.web24.net.au
        serial  = 2016060205
        refresh = 7200 (2 hours)
        retry   = 3600 (1 hour)
        expire  = 604800 (7 days)
        default TTL = 3600 (1 hour)

------------
------------
Got answer:
    HEADER:
        opcode = QUERY, id = 76, rcode = NOERROR
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 4,  authority records = 0,  additional = 0

    QUESTIONS:
        somedomain123123.info.com.au, type = A, class = IN
    ANSWERS:
    ->  somedomain123123.info.com.au
        internet address = 52.5.111.221
        ttl = 59 (59 secs)
    ->  somedomain123123.info.com.au
        internet address = 52.201.189.141
        ttl = 59 (59 secs)
    ->  somedomain123123.info.com.au
        internet address = 52.3.124.67
        ttl = 59 (59 secs)
    ->  somedomain123123.info.com.au
        internet address = 54.85.85.70
        ttl = 59 (59 secs)

------------
Non-authoritative answer:
------------
Got answer:
    HEADER:
        opcode = QUERY, id = 77, rcode = NOERROR
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 0,  authority records = 1,  additional = 0

    QUESTIONS:
        somedomain123123.info.com.au, type = AAAA, class = IN
    AUTHORITY RECORDS:
    ->  info.com.au
        ttl = 899 (14 mins 59 secs)
        primary name server = ns1.info.com.ru
        responsible mail addr = hostmaster.info.com
        serial  = 2016052612
        refresh = 7200 (2 hours)
        retry   = 900 (15 mins)
        expire  = 1209600 (14 days)
        default TTL = 86400 (1 day)

------------
Name:    somedomain123123.info.com.au
Addresses:  52.5.111.221
          52.201.189.141
          52.3.124.67
          54.85.85.70

My hosting provider is web24.com.au, which is presumably where the hosting24.com.au comes from.

  • 1
    You do too many assumptions for the minimal amount of useful information. Show us the actual output of your DNS lookup and ideally your domain name so that we can verify it for you. – Julie Pelletier Jun 2 '16 at 5:34
  • Note that you should test the DNS resolution on a different connection and computer to double check the results you receive. – Julie Pelletier Jun 2 '16 at 5:35
  • And of course the actual domain name is secret so nobody else can test this for themselves. – user1686 Jun 2 '16 at 5:39
  • @JuliePelletier Yes I've done that. The domain records are all correct. – user1751825 Jun 2 '16 at 5:42
  • @grawity I'm certain the problem isn't with the domain records themselves. I've done the query from a number of other computers, and the result are all correct. – user1751825 Jun 2 '16 at 5:47
6

Use:

nslookup
> set debug
> [mydomain].info

To see details of your DNS query.

You have probably configured primary DNS suffix on your server to com.au. And the problem probably is, that [mydomain].info.com.au exists, so that is the result you get.

  • I suspect now that for some reason it is treating the query as a host-name rather than a fully qualified domain name. This could be why it's trying to append the other names to it. So perhaps the server believes the domain doesn't exist, due to some earlier resolution error, and is now not bothering to re-query it as-is. – user1751825 Jun 2 '16 at 6:34
  • I'm still confused as to why it doesn't think my domain exists, as it resolves correctly from other computers. However I'm fairly convinced now that the computer isn't infected with anything, and that this is normal behavior. The primary DNS suffix is set to hosting24.com.au, so this actually makes sense now. – user1751825 Jun 2 '16 at 6:39
  • I really appreciate your help. – user1751825 Jun 2 '16 at 6:39
  • And did you check what the primary DNS suffix was on your server? Was it com.au ? windowsitpro.com/networking/… – Vojtěch Dohnal Jun 2 '16 at 6:42
  • 1
    @VojtěchDohnal primary DNS suffix is hosting24.com.au, which I guess is why it tried this first. When this failed, it obviously dropped the hosting24 bit and just tried .com.au. When I do the query with a trailing . it works correctly. – user3326185 Jun 2 '16 at 6:45
0

If, as you say, everything comes up correctly, then everything seems fine. Again, without the domain name to test for ourselves, we cannot verify your information for you. There are many ways that this could be affected that we cannot really go into.

You need to discuss this with your hosting provider if you believe they are doing something dodgy.

Again, if the client sites work as intended, there could be some odd, one-off weird configuration issue that is extremely hard to diagnose and is not actually affecting anything.

  • It turns out the behavior it not limited to my real domain. It does exactly the same thing with an random non-existent .info domain. I've included the nslookup results above. – user1751825 Jun 2 '16 at 6:27

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