Cisco 2920 Switch with my 837 ADSL Router

[reb999000]

To All,           

I have newly acquired a Cisco 2940 Switch and I am currently using an 837 Router (Which I have now connected the Router onto my Sever) and I have connected an ethernet cable to the Switch (1x Port) from the Router (Ethernet 1 Port).

This morning I had encounted the "System Error Message Ip Address conflict with another system on the network" Error Message on the Task Bar on one of my Clients (Win XP OS) when I had the Switch connected.

This may have something to do with DHCP configured on my Router (As I have installed DHCP on my Server).

Please Note* I have screen-shot one of the messages from the Event Viewer from the Client for your further information.

I would be very greatful for any assistance in regards to this.

Bob.

[Leo Laohoo]

This may have something to do with DHCP configured on my Router (As I have installed DHCP on my Server)

That's not it.  Maybe someone's dynamically configured the IP address.

[John Blakley]

If you have two dhcp servers on the network serving the same range, it could be your problem. I would delete the scope from the router and use the one on the server.

Hth,
John

Sent from Cisco Technical Support iPhone App

[reb999000]

John Blakley,

In relatiion to the DHCP on my 837, here is an extract for your further information:

ip dhcp use vrf connected

!

ip dhcp pool DLSR

network 10.10.10.0 255.255.255.0

default-router 10.10.10.1

dns-server 10.10.10.1

Bob.

[John Blakley · Accepted solution]

Bob,

If you have a dhcp server on your Windows server for the same pool (10.10.10.0/24), you need to remove it from the router or the server. I would recommend using the Windows server one because you have more control over what you can do and it's just easier to manage reservations, etc. If you would rather keep the Windows server and remove the config from the router, you can issue "no ip dhcp pool DLSR" and it will remove the dhcp pool from the router effectively disabling dhcp on the router. This will not affect your router if it's pulling an address from a provider as a dhcp client.

If your router and Windows server are using different pools, you would have a different issue in that there could be users getting an address from one pool and other users could get an address from another pool. This would probably cause issues like some users not being able to surf the web, etc.

HTH,
John

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[reb999000]

John Blakley,

This had done the trick! Many Thanks for that mate!. However I kept the "ip dhcp use vrf connected" command on the 837.

Bob.

[mfurnival]

That MAC address belongs to a Cisco device (http://coffer.com/mac_find/?string=001cb1)

So your client is conflicting with an address configured on either your switch or router.