Re: SSh internal window size.. (again)

From: monster (m0nst3r_at_comcast.net)
Date: 04/29/04

  • Next message: Tobias Speckbacher: "private keys and users access to them"
    Date: Thu, 29 Apr 2004 06:56:14 +0000
    To: secureshell@securityfocus.com
    
    

    the tcp ip send recive can be changed with sysctrl for the kernel, but the higher the size the more risk you have of corruption
    bsdvualt.net http://bsdvault.net/sections.php?op=viewarticle&artid=35
    as far as changing the size for just ssh
    no clue,, hope this helps
    On Wed, 28 Apr 2004 17:54:02 -0700
    Julian Elischer <julian@vicor.com> wrote:

    > sshd:
    > openssh version sshd version OpenSSH_3.5p1 FreeBSD-20030924
    > ssh:
    > OpenSSH_3.5p1 FreeBSD-20030924, SSH protocols 1.5/2.0, OpenSSL 0x0090701f
    >
    > So, I'm ssh-ing data from machine A to machine B using sftp.

    > with ping times of 60ms, I can't get over 600KB/sec
    >
    > looking at the SYN packats going over the wire, the negotiation looks like:
    > A->B S 1041192722:1041192722(0) win 65535
    > <mss 1460,nop,wscale 2,nop,nop,timestamp 20289777 0> (DF)
    > B->A S 1916098679:1916098679(0) ack 1041192723 win 57344
    > <mss 1460,nop,wscale 0,nop,nop,timestamp 616601895 20289777> (DF)
    >
    > the recv and send default buffer sizes are set to 128K, on both sides
    > window scaling is enable on both sides,
    > so one would think that larger windows would result and data would flow
    > faster, but..
    > no. it looks as if..
    >
    > (1) there is an internal windowing going on in the ssh protocol with a 64K
    > window size.. Is this changeable?).
    >
    > (2) sshd opens it's socket with a 57KB window anyhow, despite the
    > higher default window size.. is this true?
    >
    > Can these things be changed? it's be nice to be able to use ssh
    > to transfer data at the available bandwith..
    >
    >
    >


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