I have the following network :

One Router : CISCO 860 (In : ADSL, Out : Yellow Ethernet Cable) Two Cable Panels

Rack One : PANEL 24 ports (22) - DT24F
Rack Two : PANEL 24 ports (22) - DT24F

Switches :

Rack One : 3Com Baseline Switch 2125-G 
Rack Two : 3Com Baseline Switch 2024

I have cable between the two switches (marked in blue)

the problem I have, is some of the computers are not connected to the internet, they dont get the correct IP address using DHCP, and some of them working perfectly.

Please notice the following, I connected the yellow cable to the green port (25) and some of the computers are working and some of them are not

What could be wrong in this network ? Pic : enter image description here Thanks

closed as unclear what you're asking by joeqwerty, mdpc, Andrew Schulman, Jenny D, kasperd Mar 17 '15 at 13:08

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  • 1
    When you say that some of the computers 'dont get the correct IP address using DHCP', do you mean they are receiving a DHCP IP address, but it is on the wrong subnet or something else? – cpt_fink Mar 17 '15 at 5:10
  • they get the wrong ip not given by the router, – salahy Mar 17 '15 at 18:22

You may find port 25 is a management port so may only allow traffic from itself. You can plug the router into any port so try that first. Alternatively you may have VLANS setup incorrectly especially if you use IP phones. If this is the case you will need to setup the Blue ports to be trunk ports.

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