routing from dhcp server to switch

found it

http://kb.netgear.com/app/answers/detail/a_id/21985

ok now im really confused as i dont know what switch to get the L2 or L3 switch as i have found the page to configure the L3 switch for dhcp relays

http://kb.netgear.com/app/answers/detail/a_id/21989

can anyone help as im really confused

It may be a little more complex than you think AND Netgear has also blurred the lines between what they consider layer 2 & layer 3 switches making the decision even more challenging.

First - background - traditionally L2 switches do not route, L3 switches do - so, at least in theory - you need an L3 switch to do what you want - another option is to use an L2 switch and a router that supports VLANs.

Second - for what you are trying to do - you need to use something called DHCP relay - which is where a device known as an agent will relay the DHCP request from the VLAN where the address is required to the VLAN where the DHCP server resides - the DHCP agent can be on a PC with a static address, or, the L3 switch, or the router linking the VLANs - so whatever switch you choose you need to make sure it supports DHCP relay.

Third - your DHCP server also has to be able to work with a relay agent or you won't get the address you need, where you need it - not all DHCP servers can do this.

Awesome thankyou for your reply, basically in using MS DHCP server and i have 4 network scopes, and im thinking of buying the M4100 D12G and it says it does dhcp relay so Il get the switch to dhcp relay to my dhcp server, or wont that work?

Ive noticed you can have a dhcp relay on the dhcp server instead of on the switch, what's best practice

robina_80 wrote:
Awesome thankyou for your reply, basically in using MS DHCP server and i have 4 network scopes, and im thinking of buying the M4100 D12G and it says it does dhcp relay so Il get the switch to dhcp relay to my dhcp server, or wont that work?

Check the DHCP server - does it support option 82 - the versions I have used (upto 2008) don't - 2012 might.

robina_80 wrote:
Ive noticed you can have a dhcp relay on the dhcp server instead of on the switch, what's best practice

The DHCP relay needs to be on the LAN segment or VLAN with the clients that need the address in order to relay the DHCPDiscover broadcast to the DHCP server - if you're going to put a DHCP server on every segment (or VLAN), why use DHCP relay at all?

Option 82 what is that?

I was hoping you weren't going to ask that - open the DHCP server, pick a scope and look at scope options - the scope options are where you set the default gateway, DNS servers, time server, etc., - option 82 is "relay agent information".

Looks like option 82 is on server 2012, Il get m4100 d12g switch and use just the dhcp relay function only,

What switch would you recommend btw to use, is the switch i said good?