server_name
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... server name, clients MAY include an extension
of type "server_name" in the (extended) client hello. The
"extension_data" field of this extension SHALL contain
...
... struct {
ServerName server_name_list<1..2^16-1>
} ServerNameList;
...
... It is RECOMMENDED that clients include an extension of type
"server_name" in the client hello whenever they locate a server by a
supported name type.
...
...
A server that receives a client hello containing the "server_name"
extension MAY use the information contained in the extension to guide
its selection of an appropriate certificate ...
... and/or other aspects of security policy. In this event, the server
SHALL include an extension of type "server_name" in the (extended)
server hello. The "extension_data" field of this extension SHALL be
...
... server name using an application
protocol and then upgrades to TLS, and if a server_name extension is
sent, then the extension SHOULD contain the same name that was
negotiated in the application protocol ...
... sent, then the extension SHOULD contain the same name that was
negotiated in the application protocol. If the server_name is
established in the TLS session handshake ...
... - "unrecognized_name": this alert is sent by servers that receive a
server_name extension request, but do not recognize the server
name. This message MAY be fatal.
...
... Security of server_name ...
... domain to ensure that this satisfies
their security needs. Apart from this, server_name does not appear
to introduce significant security issues.
...
... Implementations MUST ensure that a buffer overflow does not occur,
whatever the values of the length fields in server_name.
Although this document specifies an encoding ...
... Although this document specifies an encoding for internationalized
hostnames in the server_name extension, it does not address any
security issues ...