Re: [K12OSN] Our sad school network... Ethereal help

[aust_txv ACCESS-K12 org]

Greetings,

Can you use your network switches to help you out ?  For exmple in my 
routed network I can "sh int 0/48" on vlan1 on a switch getting
Tones of good info here...

FastEthernet0/48 is up, line protocol is up
 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
    reliability 255/255, txload 1/255, rxload 2/255
 Encapsulation ARPA, loopback not set
 Keepalive not set
 Full-duplex, 100Mb/s, 100BaseTX/FX
 ARP type: ARPA, ARP Timeout 04:00:00
 Last input 00:00:54, output 00:00:01, output hang never
 Last clearing of "show interface" counters 5w0d
 Queueing strategy: fifo
 Output queue 0/40, 0 drops; input queue 0/75, 0 drops
 30 second input rate 1144000 bits/sec, 151 packets/sec     downloads
 30 second output rate 530000 bits/sec, 197 packets/sec    clicks
    109787174 packets input, 2973623515 bytes
    Received 706157 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
    0 watchdog, 706131 multicast
    0 input packets with dribble condition detected
    306438296 packets output, 523540641 bytes, 0 underruns
    0 output errors, 0 collisions, 0 interface resets
    0 babbles, 0 late collision, 0 deferred
    0 lost carrier, 0 no carrier
    0 output buffer failures, 0 output buffers swapped out

Port 48 shows all in/out traffic internet.  The ratio of in/out will be 
different for the LTSP network.  Can you start shutting down vlans ?

Do a show interface  (sh int)  on your switches and see if the info matches 
what you expect.  Check those ports for collisions.  I had the same 
loopback problem with a bad dumb hub and found the location down to the 
building using this method.  Also say a CISCO 3534 beats and show net 
traffic (pretty green lights...) in the loopback building those lights 
where almost solid green.  I unplugged classroom by classroom until I found 
out room 112 was giving me trouble.  This does not certify if cable is good 
or bad just that the run can/can't handle data at certain capacities.  It 
might help you nail down some bad runs. Bad nics will do the same thing. 
Watch for noise.  Turn your port speed down.  Is your router OK ?  What 
does it say about this situation ?

I seriously doubt this is a LTSP/Linux issue.  But I got hacked once a few 
years ago and my 512mb RAM linux web server was dealing out the smackdown 
to other networks (DOS).  Not a pretty picture.

Tom V.