Subdomains redirected to primary domain

[phpmaven]

I have my rewrite rules set up to redirect any subdomains to my primary domain. I.E. whatever.mydomain.com or diddlysquat.mydomain.com 301 redirect to mydomain.com

My question is: Is this dangerous? Could it lead to potential problems with Google? Could this be abused by others to create duplicate content issues?

Thanks,

Mark

[Quadrille]

I see no risks there.

What used to be on the subdomaons? (why do they exist?)

[jdMorgan]

As long as you verify that a 301-redirect is returned (using a server headers checker), there is no problem.

In many cases, wild-card subdomains are set up as the default hosting account configuration. But if not, it's actually not a bad idea to implement wild-card subdomains and redirect them all to the canonical domain. This allows you to configure your DNS server --which is authoritative for your entire domain-- to prevent others playing 'games' by defining one or more of your subdomains on DNS servers that they control or have compromised.

Jim