Strage Problem

[cimd]

Hi!

I'm experiencing some problems with my network:

I Have a swith connected to the backbone. There I have 2 PC's (OK) and another switch. All lights are ok.
In the 2nd switch I have anoteher switch. Light is OK in both.
In the trird one I have 6 PC's.

All lights are on, and everithing seems to be OK. But I can only see the first 2 PC's. Or even more, I see (with network neighborhood) some of the final PC's but I can't reach them. (no ping)

If I change the cables I get the same problem, so this seems not to be the problem.

Any ideas?

 

[bierhunter]

We may need a little more info.

Are they managed switches, and can you go into the switch and see the MAC address of the PCs? If you can, then you are good up to layer-2. Also, make sure your speed and duplex are negotiating properly for each host. You may have to set it manually. If you do set it manually, do it at the switch and the host. Speed and duplex mismatch will cause major packet loss. You can see what looks like a good link, but have problems getting data through.

Here's something to try if you're using DHCP, and if they are Cisco switches, it may be spanning tree related. Make sure you have portfast turned on for the ports that the PCs are connected to (not the ports the switches link to each other on). You could be experiencing timeouts due to the delay in STP negotiation when the PC comes on (could be up to about 50-seconds). This could cause your PCs to not be getting an IP address. Turning portfast on will kill the delay and allow them to work immediately.

That's just one possibility. Good luck.

 

[codeman820]

Are you using Static IP or DHCP?
if you're using static IP, make sure all IP are on same subnet and subnet mask(ex. 1.1.2.1, 1.1.2.2, 1.1.2.3...254; 255.255.255.0)
If you're using DHCP, make sure the 6 PCs on the end of your daisy chain actually picked up the IP address, then ping it using the ip address it picked up not "host name".

If all the above fail, check the ports you used for uplink to your switches is actually an uplink port(some switch comes with a button to make the designate uplink port to be uplink or normal).

lastly, use crossover cables to uplink all your switches if you're using CISCO switches(2924, 3548 etc...)

Good Luck

 

[cimd]

Thanks for your help.

I (finally) solved it. It was an easyer(?) problem: the switch itself had a problem. As soon as I changed it, it worked. It looks like it can not resend the signal for a "long" distance.

Thanks a lot!!