MORE THAT ONE DOMAINE ON THE SAME IP

[Patrick]

I have many domaine names
firstname.com
secondname.com
xxxname.com

I have a DNS ip:aaa.aaa.aaa.aaa
I have a WEBSERVER ip:aaa.aaa.aaa.aaa

I configure my DNS like that:

firstname.com A record => aaa.aaa.aaa.aaa
www.            CNAME record of firstname.com

secondname.com A record => aaa.aaa.aaa.aaa
www.            CNAME record of secondname.com

xxxname.com A record => aaa.aaa.aaa.aaa
www.             CNAME record of xxxname.com

that the correct method ?
or I can  create a CNAME for secondname.com who point to firstname.com ?

I use WINDOWS2003

many thanks for all your help

Patrick