Why flush dns often doesn't work

Question

After we change name server we often want to see how our new site look like.

Sometimes the name server hasn't propagated properly to our site.

So we flush dns.

It doesn't work. It never work

C:\Users\jim2>ping goldslady.com

Pinging goldslady.com [50.87.145.204] with 32 bytes of data:
Reply from 50.87.145.204: bytes=32 time=220ms TTL=51
Reply from 50.87.145.204: bytes=32 time=213ms TTL=49
Reply from 50.87.145.204: bytes=32 time=213ms TTL=51
Reply from 50.87.145.204: bytes=32 time=211ms TTL=49

Ping statistics for 50.87.145.204:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 211ms, Maximum = 220ms, Average = 214ms

C:\Users\jim2>ipconfig /flushdns

Windows IP Configuration

Successfully flushed the DNS Resolver Cache.

C:\Users\jim2>ping goldslady.com

Pinging goldslady.com [50.87.145.204] with 32 bytes of data:
Reply from 50.87.145.204: bytes=32 time=225ms TTL=51
Reply from 50.87.145.204: bytes=32 time=207ms TTL=49
Reply from 50.87.145.204: bytes=32 time=214ms TTL=49
Reply from 50.87.145.204: bytes=32 time=205ms TTL=49

Ping statistics for 50.87.145.204:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 205ms, Maximum = 225ms, Average = 212ms

C:\Users\jim2>

Answer 1

When you flush your DNS, you are only invalidating your local cache for name resolving. You are still being fed old results because your ISP caches DNS records as well. In order to see the actual changes you must either:

• wait until the TTL (time to live) specified in your DNS entry expires, OR
• force a local change using the hosts file (in that case you might be the only one able to access the live site just yet)

Debugging live DNS queries

For a service that directly queries the name servers, without using any cache, visit: http://www.dnswatch.info/

There you can see the route it does to reach to your A record (or other types).

Another useful tool in cmd you can use is nslookup. In your case:

nslookup -type=A goldslady.com 8.8.8.8

will yeld results using the Google Public DNS server.

Hope it helps!