Re: ssh type of service (tos)

From: Keld Jørn Simonsen (keld_at_dkuug.dk)
Date: 09/23/05 

Date: Fri, 23 Sep 2005 17:47:35 +0000

Den Fri, 23 Sep 2005 09:35:37 -0400. skrev Richard E. Silverman:

>>>>>> "KJS" == Keld Jørn Simonsen <keld@dkuug.dk> writes:
>
> KJS> Den Thu, 22 Sep 2005 20:46:57 -0400. skrev Richard E. Silverman:
> >>>>>>> "KS" == Keld Jørn Simonsen <keld@dkuug.dk> writes:
> >>
> KS> Hi I am using openssh for a number of things, including file
> KS> transfer and mirroring, and I would like to be able to do traffic
> KS> policing, such as downgrading the priority of packet of a scp
> KS> transfer. How can I do that? I looked in the man pages and
> KS> googled 'openssh typeofservice' but I did not seem to get anything
> KS> I could use.
> >>
> KS> I thought maybe adding a keyword 'TypeOfService' for .ssh/config,
> KS> that also could be used by the ssh and scp -o flag could do what I
> KS> wanted.
> >> There's nothing in OpenSSH that can do this -- nor can you do it
> >> in the network, because the difference between an SSH connection
> >> carrying terminal traffic and one doing scp is invisible to the
> >> outside world (at least explicitly), the protocol being encrypted.
>
> KJS> Packets are packets an tos are a fundamental part of the packet
> KJS> structure. So could the tos be set *after* doing the encryption?
>
> Of course, if OpenSSH were doing it. I wrote that you can't do it "in the
> network" -- that is, apply TOS to the IP packets which make up an SSH
> connection externally depending on whether it's doing scp, because you
> can't tell from the outside.
>
> Darren mentioned that OpenSSH already sets TOS appropriately, which I
> should have said; my point was that it doesn't allow you to set it
> yourself, which is what I thought you were asking.

Yes, I asked for it to be done eg by an -o option.

I see that on my newer system scp sets tos to 0x0 - which was not done on
my older system.

I wonder how openssh finds out how a session is interactive or not. I do
use openssh for a number of purposes, including rsync and https. https
should be interactive, normally. Anybody care to enlighten me how it is
determined that a session is interactive? (I know, the documentation is in
the source...)

Best regards
keld

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