I have a domain named: mydomain.com. The website mydomain.com and some sub domain like sub1.mydomain.com, sub2.mydomain.com are hosting on a shared hosting (public IP address:

Now, i want to hosting a sub domain: sub3.mydomain.com on a windows server VPS. This VPS has no relation with the above shared hosting (not in the same LAN, not same provider). This VPS has public IP address:

Following several guides on the internet, i have deployed sub3.mydomain.com on IIS on the VPS with some information:

Host name: sub3.mydomain.com

Binding: type http on port 80 with IP Address: *

On VPS's DNS Manager tool, I have created a Primary zone in Forward Lookup Zones named mydomain.com.

Inside this zone, i create a New Host (A or AAAA) record with name sub3 and the IP address to

On the domain manager page of domain provider, I have configure:

host: sub1 type A point to

host: sub2 type A point to

host: sub3 type A point to

I have also enabled some firewall rules on VPS:

File and Printer Sharing (Echo Request - ICMPv4-In)

World Wide Web Services (HTTP Traffic-In)

World Wide Web Services (HTTPS Traffic-In)

The sub1, sub2 subdomain and top domain (mydomain.com) work well but the sub3.mydomain.com's server DNS address could not be found. How can i make it work? I did some step wrong?


On VPS's DNS Manager tool, ...

This part is unnecessary, if the VPS is not used as a DNS server for your domain. If the problem is

sub3.mydomain.com's server DNS address could not be found

it's not (currently) about IIS or firewall rules but the DNS servers alone. There might be something wrong with them, too, but we couldn't know. So, let's focus on the DNS first:

  • See the documentation of your DNS provider if there's some delay before changes takes effect, or if you need to confirm the changes somewhere.

  • Check your DNS servers from whois, so that you are configuring your zone in the right place. (If you now installed a new DNS zone on your VPS without delegating control over your DNS to it, it might be that you have also done similar things before and don't even know where your authoritative DNS servers actually are.)

Without knowing the actual domain we can't help any further.

  • Yep, It doesn't look like an issue of IIS or firewall because if have added binding to the IP address and i can access website via ip address directly.As you said the change in DNS Manager tool is unnecessary so i should remove the Primary Zone right? I have never used this tool before and in fact i have no idea what it used for. – khoa_chung_89 Jun 18 '17 at 5:55
  • It looks like an issue of DNS provider. Normally it takes 12 hours to update but this time it takes 2 days :) – khoa_chung_89 Jun 19 '17 at 7:50

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