apache 2.2 - Subdomains work fine, but redirect to main when using CNAME

I have a server with multiple websites in subfolders that I want to give their own domains. I'm got two subdomains setup using VirtualHost as such:

    DocumentRoot "/var/www/ex1"
    ServerName ex1.domain.com




    DocumentRoot "/var/www/ex2"
    ServerName ex2.domain.com

They are setup as A records in my DNS, and they work fine when accessing ex1.domain.com and ex2.domain.com, and the main domain www.domain.com works as well.

However, when I setup their main domains, www.example1.com as CNAME record redirecting to ex1.domain.com, visting www.example1.com shows me www.domain.com and not ex1.domain.com as it should.

What am I doing wrong?

Answer

ServerAlias directive should do the trick:

    DocumentRoot "/var/www/ex1"
    ServerName ex1.domain.com
    ServerAlias www.example1.com




    DocumentRoot "/var/www/ex2"
    ServerName ex2.domain.com
    ServerAlias www.example2.com