DNS Servers Open to Public Query
This is not an exhaustive list of publicly accessible DNS servers. There are more, those listed below are a subset, and may be better or worse than others.
|18.104.22.168||Global (routed via Anycast)|
|22.214.171.124||Global (routed via Anycast)|
|126.96.36.199||OpenDNS||Global, mainly US (routed via Anycast)|
|188.8.131.52||OpenDNS||Global, mainly US (routed via Anycast)|
|184.108.40.206||Level 3||Probably global (routed via Anycast)|
|220.127.116.11 ||Level 3||Probably global (routed via Anycast)|
NSLookup is a Name Server Lookup/Query tool which exists in both Unix and Windows distributions, and generally speaking, functionaly the same regardless of which version you're using. To start, run
nslookup from the command line.
||Displays the DNS server(s) currently being used by nslookup|
||Changes the DNS server being used/queried to 18.104.22.168|
||Attempts to resolve |
||Attempts a reverse lookup for IP |
||Set query type to |
||Set query type back to all records|
For example, to find the email exchange servers for a particular domain...
> set q=mx > microsoft.com Server: [22.214.171.124] Address: 126.96.36.199 Non-authoritative answer: microsoft.com MX preference = 10, mail exchanger = mail.messaging.microsoft.com >
One of the features of DNS is the way that records get cached around the globe. Meaning that any changes to existing records have to ripple around. Generally changes take up to 72 hrs (3 days) to take effect.
However, you can change the TTL of record to ensure that it needs to be refreshed from its authoritative name-server more frequently than normal, ensuring that any changes apply more quickly.
To view the propagation of a record around the world see http://www.whatsmydns.net
The following site has a number of tools that allow you to investigate how a domain is viewed externally/publicly...
- For further info on 188.8.131.52 see http://www.tummy.com/Community/Articles/famous-dns-server/