QoS marking for Openssh

[Damien Miller]

On Sat, 6 Mar 2010, Philip A. Prindeville wrote:

> I've been going over various services (sendmail, apache, thunderbird,
> proftpd, cyrus, etc) trying to add QoS support.
>
> I'm wondering if its worth doing for Openssh, also.

OpenSSH has labeled different ToS on interactive (IPTOS_LOWDELAY)
and non-interactive (IPTOS_THROUGHPUT) sessions for many years.

> Setting different priorities for ssh and scp make sense... but
> port-forwarding complicates things.
>
> Should the QoS be copied out of the tunneled connection?

No, that isn't really possible (forwarding traffic occurs on the same
TCP connection as session traffic) and probably would be pointless since
some devices look at the QoS on the first packet of a flow only.

> Anyone have a good idea how a connection carrying tty session traffic
> (ssh itself), plus (for example) forwarded X and LPR connections
> should label all 3 traffic types on the same connection?

Thanks to what I described above, there is no good answer for this.

-d