My application requires per-directory verification of SSL client certificates (i.e. when user requests /foo we require they have a client certificate and verify it, but when they request /bar we don't care if they have a client cerficiate). Apache has nice support for this, as the SSLVerifyClient setting can be applied on a per-directory basis, and apache will do SSL renegotiation in this instance to require the certs when needed, but not prompt for a certificate when accessing other directories.
My question is: which other web servers have this capability? Using apache to fulfil the SSL handling requirement is OK, but it is not my only requirement and I would like to know what the other options are.