Amazon ec2 Public DNS not working

With reference to this question:
How do I access my public DNS on Amazon's EC2

If I configure my security groups acccording to Windows web platform firewall rules then is there an issue? Because when I did that I couldn't access the Public DNS on web browser.

1. My security group is default and inbound rules are HTTP, RDP ,SMTPS, ICMP.




2. My instance type is t1.micro webmatrix hosting server with default security group.




3. My windows firewall is active for domain ,public and private profile.




4. I am not sure about this point. Its HTTP port 80 as shown in my security group.

I am new to Amazon EC2 and this is really urgent.

Answer

If you are using the instance as a public DNS server then you will need to have UDP port 53 open in the instance firewall (if it has one) and in the Security Group that the instance is in.

Go to your AWS management console and Select EC2. Then Under navigation click on Network & Security -> Security Groups

In the Security Groups Pane select the group your instance is in (most likely default)

Then In the lower pane click Create new Rule and select DNS

Then click Add Rule followed by `Apply Rule Changes.
The EC2 security group will now allow DNS queries to your instance.