Hi there,

I had been for over 3 days trying to solve this problem and I have no clue of what's wrong.
I'm trying to create a Dynamic DNS service using only one DNS Server (dns.firmaware.com), but created a second NS record (dns2.firmaware.com) with the same IP address.

First of all I've created a small app in VB .net that updates (using WMI) Microsoft DNS Server whenever an IP change was reported.
It creates different zones for each sub-domain and adds NS records, updates SOA record to change the TTL and MinimumTTL and finally adds/updates the A record.

I know that zone creation/update is working fine because I tested my VB .net several times and checked that Microsoft DNS entries were created/updated.

After checking all that I created a record like “test.gimmeall.com” and resolved it from my home PC. Using “ipconfig /displaydns” I checked that “test.gimmeall.com” had the following values:
localhost
----------------------------------------
Record data . . . . . : test.gimmeall.com
Record type . . . . . : 1
TTL . . . . . . . . . . . : 60
Data length. . . : 4
Section. . . . . . . . . . : Answer
A record (host) . . : 213.13.100.111

So, TTL was fine, if I changed test.gimmeall.com’s A record, after 60 seconds it would be updated, BUT that’s not happening because, after my update, when I ping the same host again it returns the same IP address and when I type “ipconfig /displaydns” it returns the following result:
----------------------------------------
Record data . . . . . : test.gimmeall.com
Record type . . . . . : 1
TTL . . . . . . . . . . . : 85823
Data length. . . : 4
Section. . . . . . . . . . : Answer
A record (host) . . : 213.13.100.111

It looks like that ISP or something else is caching “test.gimmeall.com” with invalid values, but it’s not an ISP problem because tried from different ISP companies and always had the same result.

Can you help me please?

I would be very thankful.

Regards,
Filipe Freire