Does there currently exist a system which permits webservers to restrict access to clients who have a given certification?
Yup.
What is the current certification practice?
Use either VeriSign, or build your own CA.
How easy is it to certify a given client?
Rather easy, using XCert Sentry.
Are webserver certifications sufficently secure today?
"sufficiently" by whose definition?
What are the best servers to use for secure web pages and certification currently in the United States?
=) Stronghold: The Apache-SSL-US, coupled with XCert Sentry. What else? -- Sameer Parekh Voice: 510-601-9777x3 Community ConneXion, Inc. FAX: 510-601-9734 The Internet Privacy Provider Dialin: 510-658-6376 http://www.c2.net/ (or login as "guest") sameer@c2.net