hub vs switch

[djarum]

I have remastered knoppix for use at work,
When i boot connected to a 100 meg hub everthing works,
When I connect the pc to a switch (cisco 2950t24's)
etho doesn't come up...i have intel 10/100 onboard lan.
Does anybody have any idea why this is happening or des anybody know how i can get a cisco port to emulate a hub (i.e duplex settings force 100 meg)
Thanks

[Harry Kuhman]

I have remastered knoppix for use at work,
When i boot connected to a 100 meg hub everthing works,
When I connect the pc to a switch (cisco 2950t24's)
etho doesn't come up...i have intel 10/100 onboard lan.
Does anybody have any idea why this is happening or des anybody know how i can get a cisco port to emulate a hub (i.e duplex settings force 100 meg)
Thanks
Generally a switch is better than a hub, and it should work fine in this case.

I have and use both. Bit the only reason I got the hub was to be able to use programs like Ethereal to "sniff the wire" and examine packets to be able to identify complex network issues. I almost any other case a switch is a better choice. I use switches all the time with knoppix and have seen no problems with any of the ones that I use.

Did you just throw in that top line about remastering Knoppix to add an extra variable to the problem? Does this not also happen with the original Knoppix CD, or are you telling us it is limited to your remaster?

On the assumption that it's not a remastered CD issue, it seems like it is a cisco 2950t24 issue or a cabel issue. I don't know the cisco 2950t24 but you might want to do some reading and be sure that there are no surprises. I would also look closely at your cabels and be sure that all is right. Even if they work with the switch, inspect the cabels closely. For example, I have one switch that will auto sense the cabel and correct for things if a cross over cabel is used. Other switches I have will not do this. So if I were to have a cross over cabel in the mix one of my switches would work fine, but I would have the problem you indicate if I swapped it out with a different switch.

[djarum]

It seems to be a problem with either how dhcp is "reconized" by the card in linux...
the 2 paths that i have gotten to are that
1. I have one default vlan set up for everthing on my network and knoppix doesn't like the vlan identifier and doesn't know what to do with it , while windows disregards it, if the vlaning is a ciso propitary encapuslation and used only on my cisco switches if I plug a hub into one of my cisco switch ports I am wondering if the switch is smart enough to parse the dhcp request without sending the vlan idenitifer and the linux box works correctly.
2. A portfast setting on the switch ....I am wondering if I am having spanning tree type issuses and turning on portfast on the affected ports would speed up my blocking and transport across my lan.
the linux remaster works like a charm at home on my motorola router/ switch and works on my devel network at work...which is a 24 linksys etherfast plugged into my cisco 2950t's which get dhcp from a pix 515e which sits behind a 3606 cisco router......when i plug directly into my network, bypassing the hub, is when the image doesn't bring up eth0 and that is no good for my end user in this case. Even a sudo netcardcnfig will not get an ip, but plug it back into a hub and I'm fine...
Has anybody ever ran across somthing like this? or have any ideas that I could try.
I know it's not the cable...I used a bunch to test that, and the nic works fine....I know it's the switches or the pix am wondering if anybody has any settings I could try besides the 2 I mentioned above....
Thanks
and harry thanks for mentioning ethereal...I'm going to enable span and try to sniff the port in the morning and see where the negotion bombs out
thanks again

[Harry Kuhman]

1. I have one default vlan set up for everthing on my network and knoppix doesn't like the vlan identifier
Yea, I expect you're right. I've never worked with the vlan stuff, and I could see how different equipment may give different results there. My previous post was intended to apply to a simple boot of Knoppix from CD and basic switch and hub stuff, nothing complex.