VLAN routing

[yeow_km]

i currently have a flat VLAN in my network.

there is not vlan in my switch.

all goes by 172.16.4.0/22.

network device starts from 172.16.4.0/22

servers start from 172.16.5.0/22

users start from 172.16.6.0/22.

users get dhcp address from my servers.

i am told to create vlan for new network setup.

1 VLAN for network

1 VLAN for server

2 VLAN for users.

how can i create 2 VLAN for my users if I do not want to change my dhcp scoping on the dhcp server.

Can i create 2 VLAN for my users ?

1 vlan for 172.16.6.0-50 and 2nd vlan for 172.126.6.100-150 ?

can this be done ?

[Florin Barhala]

Yes you can, just subnet close to power of 2 values: Range1: 172.16.6.0-63 then range 2: 172.16.6.0-64-127.

[cadet alain]

Hi,

Yes you can if the switch supports but you'll have to change the dhcp server config and don't forget to use ip helper-address command otherwise the DHCP packets will never reach the server which is in a different vlan ( remember vlan is a broadcast domain and dhcp discover is broadcast).

Regards.

Alain.

[yeow_km]

i am using C3560G as core switch and C2960G as my access switch.

i know C3560 can do ip-helper but my boss does not want to change the dhcp server scoping.

i guess without changing the dhcp scoping, there is no point in creating 2 vlans for users as my environment is only less than 60 users.

[cadet alain]

Yes ,

you're right you can have only one user vlan and so let the scope as it is. But don't forget the ip helper-stuff.

Regards.

Alain

[yeow_km]

if I add another VLAN for voice, what are the things that I should take note ?

[cadet alain]

what are the things that I should take note ?

What do you mean by that?

Regards.

Alain.

[fgasimzade]

You will need to create a new DHCP scope for Voice (dont forget to add dhcp option 150 for tftp server)

Create an SVI with, assign an Ip address to it from your newly created scope - this will be your default gateway

Use ip helper address command if needed

thats it

[Karel Vins]

Hi,

I think that change scopes on DHCP is best solution and not very complicated.

Try to explain it to your boss:)

Regards,

Karel V.