Solved: Help..Dhcp & Data Circuits

sarfarazkazi · ‎06-03-2008

Hi,

We have a HO and 4 Restaurants which will be connected to the HO. At HO there is a existing Internet DSL and a DHCP and a Domain Controller. I have few queries:

1. The dhcp server is giving IPs in the 192.168.1.0/24 range. When I have the data circuits up and running will they be able to get IP from the DHCP server at HO?

2. We are looking at a flat network since each restaurant will have either one or 2 users.

3. If they wont be able to get IP what should be done for them to be able to use network resources from the HO.

Attached is the network diagram.

Regards

Sarfaraz

Jon Marshall · ‎06-03-2008

Sarfaraz

Almost correct. The ip helper-address will always be the same address ie. the ip address of your HO DHCP server. For arguments sake lets say it is 192.168.1.10

So yes, you create a different subnet for each site and then on each LAN interface of each 877 you need

int f0/0

ip helper-address 192.168.1.10

One other things to note. You are already using 192.168.1.x at your HO sites so for you can't use this at one of your remote sites as well. Just choose another spare subnet.

Jon

View solution in original post

Ryan Carretta · ‎06-03-2008

As a general rule, if the network is flat (one VLAN), and you have basic connectivity, DHCP will work. So long as the users are in the same broadcast domain as the DHCP server they should be able to acquire addresses from it.

Jon Marshall · ‎06-03-2008

Sarfaraz

1) It depends on how you are connected to your ISP and also what kit you are using to connect your remote sites.

2) Following on from 1) i suspect that the ISP cloud will route your traffic to the HO. In that case you will not be able to have a flat network structure. There are ways around this such a VPLS, L2TPv3 etc.

L2TPv3 you can configure if your devices support it, VPLS is a provider solution.

However it would be a lot simpler to simply create a separate subnet for each remote site on your DHCP server. And then if you are using a Cisco device at the remote sites under the LAN interface on each device

int fa0/0

ip helper-address

The further advantage of using separate subnets is that it will be easier to keep track of who is doing what on the network.

Jon

sarfarazkazi · ‎06-03-2008

Hi Jon,

Thanks for your reply. Each restaurant is going to have a 877 installed. So you are saying that on the dhcp server I will create 4 different scopes 192.168.1.0,2.0,3.0 & 4.0. Then on the each restaurant on the E0 or F0/0 interface I will configure ip helper-address 192.168.2.1 for restaurant 1, then restaurant 2 ip helper-address 3.1 and so on.

Is that correct?

Sarfaraz

Jon Marshall · ‎06-03-2008

Sarfaraz

Almost correct. The ip helper-address will always be the same address ie. the ip address of your HO DHCP server. For arguments sake lets say it is 192.168.1.10

So yes, you create a different subnet for each site and then on each LAN interface of each 877 you need

int f0/0

ip helper-address 192.168.1.10

One other things to note. You are already using 192.168.1.x at your HO sites so for you can't use this at one of your remote sites as well. Just choose another spare subnet.

Jon