Ethical Hacking

Learn to find vulnerabilities before the bad guys do! Gain real world hands on hacking experience in our state of the art hacking lab. Course designed and taught by expert instructors with years of penetration testing experience. 12 student maximum in every class. Certification attempt included in every package.
Computer Forensics Training at InfoSec Institute

Gain the in-demand skills of a certified computer examiner, learn to recover trace data left behind by fraud, theft, and cybercrime perpetrators. Discover the source of computer crime and abuse at your organization so that it never happens again. All of our class sizes are guaranteed to be 12 students or less to facilitate one-on-one interaction with one of our expert instructors.




Network Security Secure-Shell
[Top] [All Lists]
<prev [Date] next>
[Advanced]
 <prev [Thread] next>

Re: speed limitation with scp and sftp using openssh

from [Darren Tucker] Network Security [Permanent Link]
Subject: Re: speed limitation with scp and sftp using openssh
Date: Tue, 28 Feb 2006 08:49:58 +1100 
On Fri, Feb 24, 2006 at 11:31:59AM -0600, cremes.devlist@mac.com wrote:

Take a look at this [1] for an explanation. Last I heard these  
patches were not accepted into the trunk because they didn't conform  
to some style guidelines.

Corrections welcome...


Well, they didn't conform to the style guidelines (and there were other
issues[2] such as duplicated code and minor bugs, although those may have
been addressed by now) but that wasn't the main reason.

The main reason was that they're not right yet; they actually reduce
performance in some common cases (eg relatively fast networks and
slow hosts, up to 25% in my tests).  It's still doing exactly the same
amount of work so there's no fundamental reason why this should be so.

People affected enough by the BDP to seek out the patch will gain back
the performance hit and more so for them the patch is a net win even with
those problems.  For the general case it's not so clear-cut.  See:
http://marc.theaimsgroup.com/?l=openssh-unix-dev&m=112884429502318
http://marc.theaimsgroup.com/?l=openssh-unix-dev&m=112886897105941

I've been trying to find some time to go back and look at this again
but haven't been able to yet.


[1] http://www.psc.edu/networking/projects/hpn-ssh/


[2] http://marc.theaimsgroup.com/?l=openssh-unix-dev&m=112316226728255

-- 
Darren Tucker (dtucker at zip.com.au)
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.
[More with this subject...]




<Prev in Thread] Current Thread [Next in Thread>
Previous by Date:  Re: keyboard-interactive only authentication, Darren Tucker
Previous by Thread:  Re: speed limitation with scp and sftp using openssh, cremes . devlist
Next by Thread:  An Illustrated Guide to SSH Agent Forwarding, Steve Friedl
Indexes:  [Date] [Thread] [Top] [All Lists]