Is it necessary to have dedicated IP Address to in

问题:

I have a shared hosting plan. Now, my hosting company says it is necessary to have dedicated IP Addrss to install SSL certificate?

Is that true?

Can we install SSL certificate without dedicated IP address?

回答1:

If your server supports SNI (Server Name Indication), then you don't need a dedicated IP. The browser support for SNI is pretty good these days.

If your server doesn't support SNI, then yes; you need one dedicated IP address per certificate. Since the SSL/TLS handshake happens before any HTTP headers (most notably the host header) are sent, there's no way that the web-server could know which certificate to send. You can host multiple domains/subdomains on one ip/port using a SAN or wildcard certificate certificate but you'd still need at least one dedicated IP.

For more details, see http://blogs.iis.net/thomad/archive/2008/01/25/ssl-certificates-on-sites-with-host-headers.aspx