Dell D600 laptop has intermittent connectivity on Cisco 3524 switch

Check the cabling - easiest is to replace the patch cables on both sides.  Try switching ports.  Then try different infrastructure cables (the ones inside the walls - plug into different jacks).  

If you can't pin it down to an issue with the cabling, and both laptops are doing it, maybe you should look at the drivers on the NICs in the laptops - do you have other laptops of the same kind which have no problem?

Pop in some PCMCIA or USB NICs and see if there's any problems with them.

Hi choupiqueliqueur,

Since these are workstations, you shouldn't have an issue, but for kicks and grins I would enable "spanning-tree portfast" on your 3524, on the interfaces these workstations plug into.  

Also, verify that those ports are not in a blocking state using "show spanning-tree interface [PCs interface].

Also, if you do a plain-jane "show interface [PCs interface] from the switch and post that config here, we can see what error are accruing on the interface and help you out a little better.

For both laptops we've tried different patch cables on both ends, different jacks within the building, and different ports on the switch.  The original NIC drivers were like 4.XX I think, we've installed what appears to be the latest, version 7.86.  These are the only two Dell D600s we have.  Now that you mention it, these laptops did the same thing in our office on a Cisco 3548 with IOS version Version 12.0(5)WC5a.

Do you have any PCMCIA or USB NICs which you could pop into them to test?

The lines below are from the port one of the Dells are plugged into.  When the port is set to Auto/Auto or 100/Full the only noticeable errors that show up WHEN the laptop will actually gain connectivity is CRC errors and they go up rapidly.  Change the port to 10/Half and the CRC errors stop but Collisions go up (of course).  I changed the port to Auto/Auto and enabled "spanning-tree portfast" but the laptop still would not connect.  When I do a "show spanning-tree int FX/X" it shows FORWARDING.  Also, if I do a "show int status" the switch port will show up and up yet the laptop will still not connect (when set to Auto/Auto or 100/Full).  I can put a PCMCIA NIC in and it'll work fine.

Hardware is Fast Ethernet, address is 0000.0000.0000 (bia 0000.0000.0000) (MAC addresses omited to protect the innocent)
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Half-duplex, 10Mb/s, 100BaseTX/FX
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 46000 bits/sec, 20 packets/sec
     13479 packets input, 1804444 bytes
     Received 276 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast
     0 input packets with dribble condition detected
     58814 packets output, 20083474 bytes, 0 underruns
     0 output errors, 1835 collisions, 3 interface resets
     0 babbles, 0 late collision, 290 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out

Our server/desktop manager said we'd done everything but call Dell and since it seems to be a laptop hardware issue and is another contractors machine that they could take care of that.  Thanks for the assistance......

No prob.