CNAME Question

[Tom Naves]

I wondered if the following is legal:
mail.mydomain.com        IN    A                    192.168.40.135

www.mydomain.com       IN     CNAME         mail.mydomain.com
ftp.mydomain.com          IN     CNAME         mail.mydomain.com

@                                   IN    CNAME        mail.mydomain.com


I know the first two CNAMEs are o.k.  It is the third one the @ that I wonder about.  I am using this so someone can just type mydomain.com in a web browser and get the website.

Thanks,          

Tom Naves
System Administrator
Orthodyne Electronics