Strange interaction of sftp and protocol version 1

[Gordon Rowell]

As I read the manpage, you need to enable Subsystems to have the server 
support them. 

     [...]
     Subsystem
             Configures an external subsystem (e.g., file transfer daemon).
             Arguments should be a subsystem name and a command to execute up­
             on subsystem request.  The command sftp-server(8) implements the
             ``sftp'' file transfer subsystem.  By default no subsystems are
             defined.  Note that this option applies to protocol version 2 on­
             ly.
     [...]

Are both of the following statements meant to be true?
	- Subsystems must be defined for the server to support them
	- Protocol version 1 does not support subystems

For Linux, I need the following to enable sftp:

    Subsystem      sftp    /usr/libexec/openssh/sftp-server

However, if I comment out/remove this line and restart sshd, I can still
start sftp when using Protocol version 1. 

  [gordonr at icedvovo]$ sftp timtam
  Connecting to timtam...
  Password: 
  Request for subsystem 'sftp' failed on channel 0
  Connection closed

This is fine - no DSA key, so fallback to password, then fail as sftp is
not enabled.

  [gordonr at icedvovo]$ sftp -1 timtam
  Connecting to timtam...
  Enter passphrase for RSA key 'gordonr at xxxxx': 
  sftp> 

OK, we have an RSA key, which works and then sftp starts and works.

Is this the correct behaviour?

Client and server are openssh-2.5.2p2-1.7.2

Gordon
--
  Gordon Rowell                         gordonr at e-smith.com
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