I had a problem using selfssl.exe (part of the IIS 6 resource kit) to generate more than one self-signed certificate on a specific server. The issue came up after I created a second self-signed certificate with a different CN. The certificate was installed on a separate site (same IP different port) than the first one I generated. The behavior was very strange. As soon as I generated the second certificate, the site with the first certificate would not load at all. If the certificate was removed, it worked fine. So, I regenerated the first certificate with selfssl.exe and the second stopped working. After some searching, I found that some others have had this problem as well: http://blogs.msdn.com/david.wang/archive/2005/04/20/SelfSSL-Bug-with-websites.aspx. These certs have always worked fine, but I think it may be best to limit use to one self-signed certificate per server. Oh, and the blogs post mentions a new version…it doesn’t work either. The only way to get it to work is with ssldiag, but it is not a trivial process.