[K12OSN] Tuning LTSP Performance

[Rob Owens]

On Fri, Aug 29, 2008 at 11:41:42PM -0400, Terrell Prude' Jr. wrote:
> Robert Arkiletian wrote:
> >2008/8/29 Terrell Prude' Jr. <microman at cmosnetworks.com>:
> >  
> >>2.)  If you're running LTSP of any sort, it's assumed that you're running,
> >>at a minimum, a switched 10/100 environment (if not, then you really 
> >>should
> >>be!).  Unless A.) it's a managed switch capable of port mirroring, and B.)
> >>you control said switch, you can sniff *your* traffic, but not other
> >>peoples.  To keep the Les Mikesells of the world happy, I'll point out 
> >>that
> >>yes, you could sniff the server if it's physically accessible.  But in 
> >>God's
> >>name, I hope you have it secured physically so's to (largely) prevent 
> >>that!
> >>    
> >
> >Please enlighten me Terrell. I don't understand how having access to
> >the server is a vulnerability in terms of sniffing packets. One must
> >have root access to be able to use a program like tcpdump or wireshark
> >to capture packets. So if they don't have root how can they sniff?
> >  
> 
> Easy.  Say you're a "curious" kid.  :-)  Just insert your own switch 
> (yes, they're available on eBay) in between the server and its network 
> drop.  On your switch, mirror the port to your laptop (laptop HD's are 
> pretty big nowadays).  Boom, you've done it, and no, it ain't that hard 
> to do.  I do this sort of thing regularly at work as part of my network 
> engineer duties when troubleshooting certain problems.
> 

Or even easier (well, at least cheaper) is to throw a hub in between the server and the main switch.  A hub mirrors all ports -- at least that's how I understand it.  Anyway, I've tried it and it works.

-Rob