[K12OSN] Tuning LTSP Performance

Terrell Prude' Jr. microman at cmosnetworks.com
Sat Aug 30 21:20:49 UTC 2008


Les Mikesell wrote:
> Terrell Prude' Jr. wrote:
>> >>
>>> Cool that's a good idea. But in any case, even without managed
>>> switches, if everyone all of sudden loses their X sessions what's the
>>> point of sniffing?
>>>   
>>
>> Sniffing's a different discussion.  ARP spoofing's more of a 
>> man-in-the-middle and/or denial-of-service attack.
>>
>
> There are variations where you spoof a MAC address to the switch so it 
> sends you some packets intended for a different port, but TCP retries 
> will soon send another copy that keep the original destination from 
> noticing that anything is wrong.
>
True.  That's what I meant about degrading the X11 connection earlier, 
due to the TCP retries.  It is effectively a "somewhat nicer" DoS 
attack.  You'll probably notice it more if you're playing something like 
TuxType.

Port security on the switch can help deal with this issue if it becomes 
a problem operationally.  Personally, that's what I like to do when 
Layer 8 lets me do it--physically secure the LTSP server, and do port 
security on the switch ports to help mitigate this sort of thing.

--TP





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