[Beowulf] passwordless "rsh" login

Robert G. Brown rgb at phy.duke.edu
Mon Jul 12 13:15:00 PDT 2004


On Fri, 9 Jul 2004, Trent Piepho wrote:

> On Fri, 9 Jul 2004, Robert G. Brown wrote:
> > this three or four times.  Things wrong with rsh:
> >  a) no security (as in "bleeding wound" in an open network)
> >  b) no environment passing
> >  c) no tunnelling/port forwarding
> >  d) no intrinsic X11 support
> >  e) archaic and easily spoofed/snooped authentication mechanism (see a))
> >  f) terrible passwordless login control
> >  g) more or less frozen, unsupported code
> 
> For starting jobs on a cluster with a private network, only b and g really
> matter, and then not that much.
> 
> > Things good about rsh:
> > 
> >  h) relatively fast
> 
> For passing data over gigabit ethernet, rsh/rcp vs ssh/scp is about four times
> faster, depending on the CPU.

...but, for most applications, this is fairly unimportant -- four times
a small number still being pretty small.

> 
> > Things bad about ssh:
> > 
> >  i) relatively slow
> >  j) cannot select "no encryption" as option even on secure networks
> >  k) evil tty disconnect "feature" that requires ~. escapes (nested yet)
> > to leave a job backgrounded from an ssh session.
> 
> What is so annoying about these things is that they didn't used to be
> problems with ssh.  They were "features" added intentionally.  I cannot
> stand the "we know what's best for you" attitude.

Amen.  I totally, overwhelmingly agree with you.  Given that j is the
cause of i, having a no encryption feature would leave you with
relatively cheap host authentication (a good thing) and a fast
connection.  k just makes me steam -- I can't see why they added this at
all, as it does nothing but annoy people AFAICT.  Why prevent
disconnected/background tasks?  Just pointless...

   rgb

> 
> 
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-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu






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