[gentoo-user] Restrict site access by SSL Client Cert?

[Tanstaafl]

Hi everyone,

I know that you can restrict access to a certain site using either Basic 
HTTP Auth or Digest Auth, but I was wondering - can you do the same with 
an SSL Client Certificate?

I'd like to prevent access to an ancient web based database to only 
users that have a Client Cert that I created for them installed.

Is this possible? I'd also like to provide for IP based exceptions if 
possible, but if I can't do both, I'll just install the Cert for everyone.

Thanks,

Charles