Tag Info

Hot answers tagged

23

Basically, it's what the name says it is. An authoritative answer comes from a nameserver that is considered authoritative for the domain which it's returning a record for (one of the nameservers in the list for the domain you did a lookup on), and a non-authoritative answer comes from anywhere else (a nameserver not in the list for the domain you did a ...


19

Not really, no. This is all about the difference between forward and reverse DNS lookups. A forward lookup is the standard name->IP lookup. So, you would have to know all the names in advance. What you want is to do an IP->name lookup, but somehow get all the names you've applied in your Apache config and in DNS as A records (or CNAMES or whatever). What ...


12

You need to use an = after -type: nslookup -type=srv _ldap._tcp.DOMAINNAME


10

I believe nslookup is used to test a DNS server itself, as opposed to utilizing your HOSTS file. http://support.microsoft.com/kb/200525 seems to indicate as much. Try just a simple ping. Does ping myMachine.MyDnsSuffix resolve to the loopback address you have specified in your HOSTS file?


10

It appears from what you're saying that the request for windows.cs is going to the ISPs DNS server now and again. The nxdomain result is then cached by Windows' DNS client, and thus used for any retries with a web browser, ping etc. Clearing the cache (ipconfig /flushdns) should force the Windows DNS client to retry the query, but there's no guarantee it ...


10

It's the default behaviour of dig not to use the search-option. From the manual page: +[no]search Use [do not use] the search list defined by the searchlist or domain directive in resolv.conf (if any). The search list is not used by default. Edit: Just add +search to make it work, like dig +search myhost.


9

Nslookup will try to resolve the name for the ip address of the DNS server configured as the primary DNS server on the client by performing a reverse lookup of the ip address. If you don't have a rDNS zone set up for your network/subnet you'll get the "server unknown" message as nslookup will be unable to resolve the name for the ip address. It's not an ...


8

You actually almost had it. On both window (at least my Win7 box I have here) and Ubuntu you would do nslookup -type=SRV _ldap._tcp.mydomain.com (notice the single dash)


8

The answer you've received is essentially a cached or forwarded response from your local DNS server. Basically, a non-authoritative name server is one that does not contain the records for the zone being queried; your local DNS is likely not going to have Google's name records, for example. You can get the name servers that are authoritative for a given ...


8

Multiple A records for a single host lookup is commonly known as round-robin DNS. It is a feature It is related to high-availability and load-sharing Yes Be advised early on that round-robin DNS is at best a mixed-bag. For more information, please consult the following resources: http://www.zytrax.com/books/dns/ch9/rr.html ...


7

Neglecting to remove the old address is exactly what happened. It's not something that would occur when the old record is still in cache when the new one is added or something like that - a different new answer always fully replaced an old answer for a RR in a cache. There's a record for the old address somewhere in the zone file, and a record for the new ...


7

You've configured the client to lookup against your internal DNS for its primary, and an external DNS server as a secondary? You have a race condition; if the internal DNS happens to be too slow to respond, then the client gets an unusable response from the public DNS server. ping is using the cached response from the lookup against the external DNS ...


7

You can only ask a DNS-Server if it has a specific record. So, no there will be no such tool for DNS. Edit Zonetransfer is of course a possibility if it is available.


7

It's not possible to do it with the DNS protocol itself, because typically there's only one PTR record for each IP address, even though there may be many A records pointing at that IP address. However some companies (e.g. http://www.ip-adress.com/) have managed to compile databases containing what you're after by storing the results of a whole load of DNS ...


7

Your server isn't returning a reverse lookup for its name. That's why you're seeing "Unknown" there. You'll need to create the appropriate reverse lookup zone to allow your server to reverse-resolve its own IP address back to its name.


7

Sadly, the answer here is "it depends". The factors it depends on will vary with the domain and how the owning servers are set up as well as how your own local DNS is set up. First, for example, regarding the NS records returned: it is perfectly allowed to randomise the order in which those records are returned, so the order may differ each time you ...


7

First start nslookup without parameters, then type set type=txt, then type the domain name. nslookup <enter> set type=txt <enter> villagevines.com Example C:\Users\wilfried>nslookup Default Server: mydnsserver Address: 192.168.1.1 > set type=txt > villagevines.com Server: mydnsserver Address: 192.168.1.1 *** No text (TXT) ...


7

There is not, because it's likely that the DNS server for facebook.com is only serving you with those three: it's simply not telling you about the others. This is done for many reasons: some servers will be located close to you, geographically, and so the DNS server will prioritise those IPs to you. As a measure to curb potential DoS attacks, the DNS ...


6

dig wants the '-x' flag for reverse lookups on an IP. Alternately, you can use the full form, 'dig PTR 122.56.74.71.in-addr.arpa.'


6

You're not finding a lot of articles describing what you're seeing, I'm guessing, because the vast majority of the Active Directory deployments aren't using IPv6. The addresses displayed in your nslookup output show me that you are definitely using IPv6 (which also makes sense given Comcast as your ISP). Your clients are getting IPv6 DNS from your ISP (a ...


6

On the CentOS box I have to hand dig +short www.google.com 74.125.132.147 74.125.132.99 74.125.132.103 74.125.132.104 74.125.132.105 74.125.132.106 If you only want one address then dig +short www.google.com | head -1 or dig +short www.google.com | tail -1


5

Because the owner of the domain name set it up that way.


5

This happens in dual stack IPv4/IPv6 environments where the machine doing a DNS lookup sends requests for AAAA and A records on the same socket, expecting to receive two replies back. This is default behavior for relatively recent versions of glibc. The Juniper firewall, however, drops the connection after the first reply comes back. The Juniper knowledge ...


5

Because google has different DNS records for the root zone and the www zone.


5

No, you will not easily find such information from dig or any other tool that queries the DNS for a few reasons. First, NS records do not point at IP addresses, but at DNS names which in turn point to IP addresses. The distinction is important because the relationship of names to IP addresses is not 1:1, and the reverse of it is rDNS which is not an exact ...


5

The way I usually see this done is by having the DNS server resolve just the FQDN, but adding the domain to the search list in the DNS config on the clients. You can push this out to the clients via DHCP. I have two networks running in this way and it just works, with no issues on Windows, Linux, or Mac.


5

As SvenW and joeqwerty have said, this is pretty obviously not your job (as evidenced by the fact that you have no access to the things you would need to change to fix the problem) -- Contact Your System/Network Administrator, report the problem with as much detail as you can, and then leave them alone so they can do their job. The most likely cause of the ...


5

First, get a high-level view of what is happening when the page loads with the help of the Firebug extension for Forefox. I will show you the exact amount of time each component of the web page takes to load. This will give you the first clue for what exactly you have to investigate. If it is indeed a DNS problem, one of the most powerful tools to debugging ...


4

Download BIND for Windows, there is a Windows port of dig in that. You should use dig instead of nslookup. If you're a Powershell fan (like me) you can also download the Powershell Dig Cmdlet which should get TXT records for you directly within powershell. Good stuff. PS> Get-Dns -Name mydomain.com -Type TXT


4

Another possibility is that the client machines on the network are going through an HTTP proxy server that picked up on the IP address change before they did.



Only top voted, non community-wiki answers of a minimum length are eligible