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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
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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....

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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...

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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 ?
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.
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ASKER

what about other computers that are in Vlans 20,30,40,50. they are not in same vlan as the DHCP server ???
Then you'll need ip helper-address statements on the interfaces for those VLANs.
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ASKER

So IP Helper-address can be configured at the sub-interface (for each Vlan) level as well as at the global configuration level ?
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ASKER

Thanks Donjohnston !!
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ASKER

Thank you all Guys!