Guys, don't repeat my stupid mistake!!!

[bwkaz]

Let's see...

(1) When your switches don't have Spanning Tree turned on, don't ever plug a crossover cable into two ports on the same switch, unless each port's "default" VLAN ID is different. Otherwise, at the first broadcast packet (e.g. an ARP request), you'll create a broadcast storm -- all the lights on every switch in your building will light up and stay on, and nobody will be able to talk to anything on the network because of all the repeating traffic.

Different VLANs may be able to be plugged into each other, but we had some issues with that as well. Don't remember exactly what they were, though; IIRC it was something to do with ARP responses or switching decisions or something.

(2) When your computer is plugged into a UPS, and the "normal" shutdown procedure for the computer is to unplug the UPS and let it power-down with apcupsd (or on windows, apcupsd or APC's PowerChute), don't unplug the power cable from the PSU instead of unplugging the UPS from the wall.



(3) When you write a program that uses WinPcap 3.x or earlier to get and set various NDIS OIDs, don't disable (or change any options on) the NIC that your program is bound to without shutting down the program. Otherwise you'll blue-screen. (The problem is a stale handle in the user-mode program. The WinPcap driver has already lost its handle to the lower-layer miniport device, but the handle that the user-mode program was given doesn't get invalidated. So the WinPcap driver blue-screens as it tries to dereference an invalid handle.)

WinPcap 4.0alpha1 and (hopefully) any later version shouldn't have this problem.

[gehidore]

can we make this the

[Main] don't do this at home - post your story here

thread?

As for me.... we spent 3 hours trying to figure out why the box we just build wasn't working, push the buttons the fans/cdrom/harddisk all spun up... but no post codes no nothing, turned out the PSU had not been plugged into the mainboard, damn switches attached to the PSU's....

[cybertron]

Let's see...

(1) When your switches don't have Spanning Tree turned on, don't ever plug a crossover cable into two ports on the same switch, unless each port's "default" VLAN ID is different. Otherwise, at the first broadcast packet (e.g. an ARP request), you'll create a broadcast storm -- all the lights on every switch in your building will light up and stay on, and nobody will be able to talk to anything on the network because of all the repeating traffic.

Different VLANs may be able to be plugged into each other, but we had some issues with that as well. Don't remember exactly what they were, though; IIRC it was something to do with ARP responses or switching decisions or something.

On that note, don't ever plug a newly installed Windows machine into your network if it has two network cards and you haven't disabled the MAC bridge that it probably decided to set up for you. It can cause your port to get automatically disabled and your network administrator to run out of his office wondering what you just did.

Oddly enough, I only plugged the one network card in, but Windows still decided to start sending out packets that tripped the loop detection on the switch.

(3) When you write a program that uses WinPcap 3.x or earlier to get and set various NDIS OIDs, don't disable (or change any options on) the NIC that your program is bound to without shutting down the program. Otherwise you'll blue-screen. (The problem is a stale handle in the user-mode program. The WinPcap driver has already lost its handle to the lower-layer miniport device, but the handle that the user-mode program was given doesn't get invalidated. So the WinPcap driver blue-screens as it tries to dereference an invalid handle.)

WinPcap 4.0alpha1 and (hopefully) any later version shouldn't have this problem.

Alright, see, that just doesn't belong in this thread. If most people can't even understand the problem it wasn't "stupid" in this context.

[M_N]

I recovered a backup from an AIX server right over the /etc of my linux box...
When I realized what I had done, I just went for a walk

[Pafnoutios]

can we make this the
thread?

Hmmm, no nested quotes, eh?
I suggest "Don't try this at home, kids."

[acid45]

Mount your partition, not your block device :P

[gehidore]

Mount your partition, not your block device :P

One I'm sure we've all done, fdisk your *disk* not partition.

[Parcival]

Time to dig up this old classic of mine. (I accidentally hit the main power button on my computer case and came to justlinux desperately crying for help)

[cybertron]

Hah, I did that on my first build. I pulled the power supply out of the box and said to myself "I better not forget to flip that switch" and promptly forgot to flip the switch (although in my defense I had a desperate hunt in between for some screws to attach the motherboard to case because they forgot to include them). I actually took all of the front panel connections off and reattached them before realizing what I had done.

Oh, and later that summer I was helping another friend build a computer, but she was going to install Windows. We got it all put together and she booted the Windows CD. Surprise! It can't find the hard drive because it was SATA and Windows doesn't support that without a floppy for the drivers. Naturally I hadn't considered that because it wasn't a problem for me...we ended up leaving her to sort that out herself because it was late and we needed to leave. I guess the stupidity here though is that Windows still requires a floppy drive for installation (which she had to cannibalize from an older system because naturally she wasn't putting one in the new one).

[bwkaz]

Alright, see, that just doesn't belong in this thread. If most people can't even understand the problem it wasn't "stupid" in this context.

Yeah, well, I needed something to use for number 3, and that was the first thing that came to mind.

[gehidore]

Time to dig up this old classic of mine. (I accidentally hit the main power button on my computer case and came to justlinux desperately crying for help)

See and this whole time I thought you were never a newbie...

[leonpmu]

NO!! It can't be!!! Are you saying that Parcival was a newbie once??? It is NOT possible!!!

[Parcival]

Hello, my name is Parcival, and I have been able to live without newbie for two months now.

[cybertron]

All at once now: "Hi Parcival".

[Icarus]

Liar, I saw you newbieing just the other day! Once the group hears about this....