SSH1 vs. SSH2 - compression level

Darren Tucker dtucker at
Fri Nov 7 11:32:00 EST 2003

Tomasz Chmielewski wrote:
> I was wondering, why setting the Compression Level was removed in SSH2,
> and if on, is always set to 6.

Unless I read it wrong, the SSHv2 protocol standard does not provide a way
to set the compression level [0].  I don't know why this is, perhaps
someone else knows the reasoning behind it?

See section 5.2 here:

Compare with the SSHv1 RFC:
(see the description of the SSH_CMSG_REQUEST_COMPRESSION packet type).

[0] Ignoring implementation-specific extensions, eg "zlib-1 at"
through "zlib-9 at" or something.

Darren Tucker (dtucker at
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.

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