Configure CIsco router for VLANS

I would like to know how to configure cisco router in the following scenarios:

Scenario 1:

We have layer 2 switches, configured with Vlans 10,20,30,40,50
we have windows DHCP Server, DNS Server in Vlan 10 configured with static IP addresses, we have also some workstatyions plugged to Vlan10 that should get their IP from DHCP.
In this case , I believe I need to configure one port of the Layer2 switch as a Trunk and connect to the router port. once this done, how should I configure my router ?

Scenario 2:
the same as Scenario one, except that I need to replace Layer2 switch with Layer 3 switch.

Please post the configuration of the router for both scenarios

Thank you

RoutersWindows Server 2003DHCP

Last Comment

jskfan

8/22/2022 - Mon

SOLUTION

tolinrome

5/13/2013

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Don Johnston

5/13/2013

I believe I need to configure one port of the Layer2 switch as a Trunk and connect to the router port. once this done, how should I configure my router ?

Create subinterfaces on the router for each VLAN.

int f0/0.1
 encap dot1q 1 native
 ip address 192.168.1.1 255.255.255.0
int f0/0.10
 encap dot1q 10
 ip address 192.168.10.1 255.255.255.0
int f0/0.20
 encap dot1q 20
 ip address 192.168.20.1 255.255.255.0
etc....

Open in new window

the same as Scenario one, except that I need to replace Layer2 switch with Layer 3 switch.

No trunk, just create SVI's for each VLAN

interface vlan 10
 ip address 192.168.10.1 255.255.255.0
 no shut
interface vlan 20
 ip address 192.168.20.1 255.255.255.0
 no shut
etc...

Open in new window

jskfan

5/13/2013

ASKER

Ok...if I understand it is mandatory to configure IP helper "DHCP IP address" in both scenarios...?

IP helper "DHCP IP Address", should be configured a the router global configuration ?

Don Johnston

5/13/2013

Not in the scenario that you outlined.

we have windows DHCP Server, DNS Server in Vlan 10 configured with static IP addresses, we have also some workstatyions plugged to Vlan10 that should get their IP from DHCP.

Since the DHCP server and the DHCP clients are on the same network, there is no need for an ip helper.

This is the best money I have ever spent. I cannot not tell you how many times these folks have saved my bacon. I learn so much from the contributors.

rwheeler23

jskfan

5/13/2013

ASKER

what about other computers that are in Vlans 20,30,40,50. they are not in same vlan as the DHCP server ???

Don Johnston

5/13/2013

Then you'll need ip helper-address statements on the interfaces for those VLANs.

jskfan

5/13/2013