fiza Posted March 10, 2019 Posted March 10, 2019 (edited) We have layer 2 switches and we are changing ISPs at our Primary School. With the new ISP we are being issued with IP addresses that we should use internally. They will split the network in 2 subnets so we can have 2 VLANs(VLAN 20 & 30). I have a DHCP server on VLAN 30 where I have set up scopes for both VLANs. If I have no layer 3 switches how can I set the IP helper address for VLAN 20 so it knows to get addresses from the DHCP server on VLAN 30? Do I need to tell the ISP to set this on their router? Edited March 10, 2019 by fiza
FN-GM Posted March 10, 2019 Posted March 10, 2019 (edited) how can I set the IP helper address for VLAN 20 so it knows to get addresses from the DHCP server on VLAN 30? Do to this you will need a Layer 3 switch. The the other way would be to have 2 interfaces on your ISP router and have them plug into each VLAN and then use their router for the helper address. Do you want devices in VLAN 20 and 30 to talk to each other? If so using the above wouldn't be optimal. Edited March 10, 2019 by FN-GM 1
fiza Posted March 10, 2019 Author Posted March 10, 2019 The ISP WILL be providing 2 interfaces on the router. I will speak to them on Monday. The devices in the 2 VLANs don't need to talk to each other.
Katy Posted March 10, 2019 Posted March 10, 2019 The ISP WILL be providing 2 interfaces on the router. I will speak to them on Monday. The devices in the 2 VLANs don't need to talk to each other. In that case just putting the DHCP server on both VLANs by giving it a second NIC should get everything working. 1
fiza Posted March 10, 2019 Author Posted March 10, 2019 In that case just putting the DHCP server on both VLANs by giving it a second NIC should get everything working.It's a hyperv virtual server. Would adding 2 virtual NICs work? Never done that before.
FN-GM Posted March 10, 2019 Posted March 10, 2019 In that case just putting the DHCP server on both VLANs by giving it a second NIC should get everything working. I wouldn't do this. It can cause all sorts of problems. You are better off using the ISP router for the helper address or using the router itself for DHCP. Also if the second VLAN used for something like BYOD or Guest WIFI it will be a security concern. 1
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