4. Global Requests

There are several kinds of requests that affect the state of the remote end globally, independent of any channels. An example is a request to start TCP/IP forwarding for a specific port. Note that both the client and server MAY send global requests at any time, and the receiver MUST respond appropriately. All such requests use the following format.

byte      SSH_MSG_GLOBAL_REQUEST
string    request name in US-ASCII only
boolean   want reply
....      request-specific data follows

The value of request name follows the DNS extensibility naming convention outlined in [SSH-ARCH].

The recipient will respond to this message with SSH_MSG_REQUEST_SUCCESS or SSH_MSG_REQUEST_FAILURE if want reply is TRUE.

byte      SSH_MSG_REQUEST_SUCCESS
....     response specific data

Usually, the response specific data is non-existent.

If the recipient does not recognize or support the request, it simply responds with SSH_MSG_REQUEST_FAILURE.

byte      SSH_MSG_REQUEST_FAILURE

In general, the reply messages do not include request type identifiers. To make it possible for the originator of a request to identify to which request each reply refers, it is REQUIRED that replies to SSH_MSG_GLOBAL_REQUEST messages MUST be sent in the same order as the corresponding request messages. For channel requests, replies that relate to the same channel MUST also be replied to in the right order. However, channel requests for distinct channels MAY be replied to out-of-order.

4. Global Requests​

4. Global Requests