I have a dotnetnuke installation now.

for example I have installed

AAA.com

BBB.com

CCC.com

all three portals work fine now. I don't need to modify any IIS setting for these portal. (Because Dotnetnuke portal is my default portal.)

But I found that if I want to setup a new potal like.

www1.DDD.com, www2.DDD.com, www3.DDD.com

It doesn't work? I have already assign the DNS information to my DNS server.

All these address will direct to the same IP ex: 140.119.2.8.

In dotnetnuke setup, all portal have related alias name also. But these three portals don't work.

It can work on Child portal only. ie: DDD.com/www1, DDD.com/www2, DDD.com/www3

Could anyone tell me how to fix this problem? 

But I didn't add any header for my AAA.com, BBB.com, CCC.com. (Because Dotnetnuke is my default website. I think all address that doesn't exist in other websites's header value should send to default website am I right? )

Why I need to add header entry for DDD.com?

Or it because I need to create www1.DDD.com, www2.DDD.com, I need to add header?

Another question is: Is there any easy way to setup IIS so that can let me easy to setup www1.AAA.com, www2.AAA.com, www1.BBB.com, www2.BBB.com.

Can I just use header www1, www2, than IIS can map the www1.AAA.com, www1.BBB.com. (All come with www1 first.). It seems not work now. I need to add all www1.AAA.com, www2.AAA.com, www1.BBB.com, www2.BBB.com  4 header entries to make it work. Is there other easy way to make the setup easier? Thank you~~~~