Why is it not possible to use Name-Based Virtual Hosting to identify different SSL virtual hosts?
Name-Based Virtual Hosting is a very popular method of identifying different virtual hosts. It allows you to use the same IP address and the same port number for many different sites. When people move on to SSL, it seems natural to assume that the same method can be used to have lots of different SSL virtual hosts on the same server. It comes as rather a shock to learn that it is impossible. The reason is that the SSL protocol is a separate layer which encapsulates the HTTP protocol. So the SSL session is a separate transaction, that takes place before the HTTP session has begun. The server receives an SSL request on IP address X and port Y (usually 443). Since the SSL request does not contain any Host: field, the server has no way to decide which SSL virtual host to use. Usually, it will just use the first one it finds, which matches the port and IP address specified. You can, of course, use Name-Based Virtual Hosting to identify many non-SSL virtual hosts (all on port 80, for example
Name-Based Virtual Hosting is a very popular method of identifying different virtual hosts. It allows you to use the same IP address and the same port number for many different sites. When people move on to SSL, it seems natural to assume that the same method can be used to have lots of different SSL virtual hosts on the same server. It comes as rather a shock to learn that it is impossible. The reason is that the SSL protocol is a separate layer which encapsulates the HTTP protocol. So the problem is that the SSL session is a separate transaction that takes place before the HTTP session even starts. Therefore all the server receives is an SSL request on IP address X and port Y (usually 443). Since the SSL request does not contain any Host: field, the server has no way to decide which SSL virtual host to use. Usually, it will just use the first one it finds that matches the port and IP address. You can, of course, use Name-Based Virtual Hosting to identify many non-SSL virtual hosts (a
Related Questions
- Why is it not possible, that two developers working on different hosts in the network check out the same developmentline from their host and commit changes on it?
- Why is it not possible to use Name-Based Virtual Hosting to identify different SSL virtual hosts?
- Can I use name-based virtual hosts with SSL certs?
