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How to configure a switch for multiple sites

I have a switch that floats between multiple sites.  We have a DHCP server that we configure IP ranges for.  What I am trying to accomplish is allowing for the floating switch to be able to be plugged into any location, grab an ip, and then hand out ip's from that range.  For note:  The switch is a Cisco 3560X.  Would I be able to put in ip helpers to the DHCP server and then perhaps also add the ip helpers of each of the routers at the locations, or any other suggestions?  Thanks!!
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Don JohnstonInstructorCommented:
You might be able to do that.  

But it probably wouldn't be very easy.

I'm assuming that since it's a 3560, you're probably doing interVLAN routing.  Which means that the SVI's (VLAN interfaces) will need IP addresses.  And those addresses will have to be the same at whatever location you connect this switch at since they're probably the default-gateways for the hosts that connect to the switch.

Now the IP addresses assigned to those SVI's can be obtained through DHCP, but you would have to create static bindings on the DHCP server to insure the switch gets the same IP address every time.

So (I think) it's possible.  I've just never actually tried it.
Metro-ITAuthor Commented:
Well, I can not give it the same ip at all the locations.  They have there own scope.  So,  10.1.1.xxx - Location A,   10.2.1.xxx- Location B,  10.3.1.xxx - Location C.   etc.
Don JohnstonInstructorCommented:
I understand that.  But at each location, you would want it to have the same address.

For example, at location A, you would want the switch to always get the IP address  This would require a reservation for that address and a manual binding of that IP address to the switch's MAC address on the DHCP server.  And if you have multiple SVI's, you would need to do that for each SVI.

And you would have to do this at each location.
Why do you need a different scope at each location?  IF you're using the 3560 to do Layer-3 routing, the subnets will be confined to the floating switch only, and there should be no harm in having a "traveling DHCP Scope" to go with your "traveling" switch, and using some dynamic routing to advertise the current location to the rest of the network.

However, if you only use the switch to temporarily expand the port capacity at a location (and not adding additional VLANs or subnets), you do not need to do Layer 3 routing on the 3560 - Just configure the management SVI to use DHCP to obtain its own IP.  Any device that connect to the floating switch will connect to the local VLAN, and DHCP requests will be forwarded to the DHCP server by the existing (permanent) default gateway (NOT by the SVI on the switch), through the ip helper addresses configured there.

Or am I missing something?  I know this is not exactly what you asked, but it seems that this is what you want to accomplish?
Don JohnstonInstructorCommented:
B is the grade given for acceptable solutions, or a link to an acceptable solution. A B grade means the solution given lacked some information or required you to do a good amount of extra work to resolve the problem. When closing the question, the asker should explain why a B grade was awarded.
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