Re: Keepalive message per channel in SSHv2

[Markus Friedl <markus%openbsd.org@localhost>]

On Tue, Jan 08, 2002 at 11:59:06PM -0800, Pankaj Bhagra wrote:
> Hi There,
> 
> I am not sure how to handle a keepalive message received on the client
> side after the session is successfully established.
> 
> Scenario:
> 
>    Inhouse implementation of sshv2 client <----> SSH Secure Shell 2.3.0
> Server
> 
> After the connection is established successfully between the inhouse
> sshv2 client and SSH 2.3.0 server, the ssh client receive the following
> message from the server side. 
> 
> 62 00 00 00 00 00 00 00-15 6b 65 65 70 61 6c 69   b........keepali
> 76 65 40 6f 70 65 6e 73-73 68 2e 63 6f 6d 01      ve%openssh.com@localhost.
> 
> This is a SSH_MSG_CHANNEL_REQUEST (0x62) message for channel id 0 (0x
> 00000000), with a string len (0x15) "keepalive%openssh.com@localhost" and have a
> want reply flag = TRUE. 
> 
> I have couple of questions related to this message:
> 
> 1. Do we support per channel keepalive messages in sshv2 protocol ? I
> couldn't find this specified in ietf drafts. any pointers ??

no.

> 2. How to handle this request ?

send a request failed message back if 'want reply' is true.

> 3. To me this message is not from the SO_KEEPALIVE, if the above said is
> true I couldn't find the generation of the message in the 2.3 code base,

it's an experimental feature in openssh.

> could anyone xplain what is happening here. Is it mandated/suggested by
> the protocol to support 2 kinds of keepalive, one at TCP level and
> another at per channel ??

no.