I was folling this guide for my website. I did all and now I have ISPConfig panel and roundcube mail. After that it said I should have ISPConfig3 acting as my name server to active mail server. And there is another guide for dns setting.
Here is my problem; in the second guide, there are 2 IPs like 64.25.171.8
and 64.25.171.9
Where did came from? Are there GoDaddy's DNS Servers?