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Mysterious Connectivity Issue

R

reicherb

Platinum Member
I am at a school that just did a new network install (servers, routers, switches, cabling). Everything is less than 1 year old. We are having a problem with some cable drops. We have plugged known good PCs into these drops and get a link but no connectivity. The drops all test as CAT5e certified. We have tried different ports on the switches. We have tried a different brand NIC. With different NICs we were able to get some connectivity but not correct. The systems that we use are Dell Optiplex GX200s with integrated 3Com NICS. With these we get no connectivity. If we connect older Compaq PCs with PCI NICs they cannot connect to our ZENworks Imaging Proxy, during boot, server, but they can log into the network and access resources. On other drops there is no problem with either type of PC.


We use NetWare 5.1
ZENworks 2.0
Cisco switches - model unknown (forgot to get it before I came home)


What might be the problem?

Thanks.
 
sounds like spanning-tree/auto-etherchannel/auto-trunking on the cisco switches (which is the default)

you need to
1) enable spanning-tree portfast
2) set trunking to off
3) set etherchannel to off

depends on your model of switches. without this stuff disable it can take upto 50 seconds from link detection for the port to fully join the bridge group. more than enough time for a modern PC to complete its boot. Also make sure speed duplex are set to auto on both sides, or set on both side of the link.

common configuration mistake - found link for ya!

host port configuration
 
Wow this place is great!!!

Are there any negative effects to the settings you suggest? I haven't read that link yet but will once I know what kind of switch I'm dealing with.

Thanks a milllion spidey07.
 


<< Are there any negative effects to the settings you suggest >>



see numbers
1) - portfast bypasses the listening and learning stages of spanning-tree and goes directly to forwarding. while this is ideal for endstations and hosts, it is BAD MOJO if you plug another spanning-tree device. USE ONLY ON HOST PORTS
2) - no auto trunking. well guess it is bad if you're trying to trunk with another switch, but in this reality the setting is desired.
3) - no auto channel. smame thing.

I generally do not like auto-magic anything. if you want to trunk then set the trunk, if you want to channel then set the channel. otherwise turn them off.
 
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