Different DHCP Scopes

[aparikh80]

I am running one DHCP Scope right now 10.10.20.xxx. I want to add a second Scope and put my servers and my PRinters on this scope. so I keep the primary as only for workstations. I am assuming this is not as easy as I am thinking.
Any good steps or recommendations on what I need to do does this require subnetting if so what do I need to do
Any help or KB's are much apprrecaited

 

[chipk]

If you have discontigous networks, (e.g. 10.10.20.0/24 and 10.10.21.0/24) you need a router to separate them and route traffic between them; or you need a switch that can perform routing. Setting up your DHCP is just a small step in accomplishing network segmentation.

 

[chipk]

A server with RRAS enabled would accomplish this for you as well. It would need to have a NIC on both segments.

http://techrepublic.com.com/5100-10879_11-5844624.html#

 

[aparikh80]

THanks. I dont want to use RRAS. I have a Cisco260XM router and all Cisco 2900 Switchs. IS thier any good location that I can read on this including all steps required?

 

[chipk]

I would start at Cisco.com with your router model's documentation. That router should have two Ethernet ports -if I'm right, that makes your job a little easier. Unless of course you're using one to connect to a high-speed cable modem. One ethernet port should already be connected to a switch. If you're using a Serial interface for your Internet, then you should have an ethernet available.

Setup is going to depend on your exact model's documentation. I'd download that from cisco.com.

But, ideally, what you want to have is VLANs and a Routing Protocol with your two networks. Your router interfaces would be configured similar to this:

Ethernet0
ip address 10.10.20.1 255.255.255.0 (assuming you've subnetted down to a class C)
ip helper-address 10.10.21.xxx (whatever your dhcp server is)

Ethernet1
ip address 10.10.21.1 255.255.255.0
ip helper-address 10.10.21.xxx (whatever your dhcp server is)

You're also going to need to configure your routing protocol on the router (rip, igrp, ospf). Let me know what you're using and I can point you in the right direction on that as well. Here's an example of how to configure RIP:

http://www.cisco.com/en/US/products...ommand_reference_chapter09186a00800ca5a4.html

You're also going to need to put your switchports on your 2900s in different vlans based on whether you want them in your server subnet or your workstation subnet. You can find documentation for doing that here:

http://www.cisco.com/univercd/cc/td/doc/product/lan/c2900xl/29_35xu/scg/kivlan.htm

If you can borrow a CCNA book, or even better a BCMSN book, from one of your Cisco pals, this type of setup is generally found in those books.

 

[aparikh80]

Thanks.
My t1 is going into the csu/dsu. From their my ethernet 1/1 is going to my lan. in the above description if primary LAN ( Servers, printers) uses 10.10.20.5 as a dhcp, I can do e0/1 as my workstations ( 10.10.21.xxx) and have it talk to 10.10.20.5 for dhcp and my subnet is 255.255.254.0.
Please let me know of any suggestions.

 

[chipk]

That is correct. What routing protocol do you use?

 

[aparikh80]

Right now I dont know. I didnt configure the router, and to my knowledge only the most basic of configurations was done on it.

 

[chipk]

After thinking about this some more, I realized that your subnetting setup won't actually segment servers from workstations. With a 10.10.20.0/23 (255.255.254.0) network, what you end up with is 510 hosts on a SINGLE, contiguous network, and if you're looking to create separate broadcast domains for your servers and workstations, this will not accomplish it.

What you need is two networks, i.e. instead of:

10.10.20.0/23, which gives you 510 usable addresses, you want:

10.10.20.0/24, which gives you 254 usable addresses for workstations and:

10.10.21.0/24, which gives you 254 usable addresses for servers/printers.

Of course, like most networks you probably only have 10-20 servers, and a couple hundred workstations; you may still be able to do this with a single class C range if you don't have over 250 nodes (sorry, hope I'm explaining this clearly). So, I apologize, but I broke a cardinal rule for network design. You're supposed to start with how many hosts you need on each network, and THEN figure out your subnetting, etc.

If your router was configured with the menu setup, you're probably running RIP or IGRP. Post back here when you find out, or just e-mail me, and I'll try to help you out:
ckempston @gmail.com