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2980G DHCP & Vlans? 2

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Hamitduk

Technical User
Nov 13, 2011
4
MX
Hope somebody can help?

I have a 2980G-A's, with a few Vlans, and I need to have the vlans pull there Ip info from a dhcp server?

Next set up a DHCP pool for that Vlan, can this be done & how?

Hami
 
Yes, I know how to do a web search, yes there is a lot of info on how to set up DHCP on a Switch, but i have found nothing on how to set it up on a Vlan on a Switch, it's a 2980G-A

Can any one help in this matter?
 
A 2980G is a layer 2 switch only and cannot be a dhcp server , that would have to be another device handing out the addresses . To create a vlan it is simply " set vlan X state active" . This creates the vlan . To put the vlan on a port it is just "set vlan X slot/port " . This is a old catos device and does not have any dhcp capability . For all user ports you should also add the command "set port host" , this turns on portfast . Whoever is doing the routing for this device for each vlan or subnet you would need to add an ip-helper address pointing to the address of the dhcp server. Such as

int vlan 25
ip address 192.232.25.254 255.255.255.0
ip helper-address <dhcp server address>
 
Ok, thanks for the response, it was a help.

Still a bit lost,

it can't be a DHCP server, got it.
can I set a vlan to get it's Ip info DHCP server?
I can set up a vlan as a sub-net with its own IP range?

What i have it two internet feeds coming in (both DHCP, both on the same sub-net), I need to separate them? So when there inside they are on two different sub-nets?

Dose this make sense?

Sorry my last CISCO class was in 1998 and I have not been working in the field for 10 years.
 
Since this is a Layer 2 switch, your vlan interfaces will need to be on a layer 3 device such as a router. To make it easy I am going to just make up some assumptions. Lets assume we have 3 vlans...
1- management lets say this is the 192.168.1.x network
100 - data and this is the 192.168.100.x network
200 - voice and this is the 192.168.200.x network

Your routers fast ethernet interface (if cisco) will connect to any of the switch ports. You will want to configure that switchport as a trunk and allow vlan 1,100 and 200 or all vlans to make it easier. On the router side you will need to create subinterfaces on that port for each of your vlans....it should look something like 0.1, 0.100 and 0.200. Each of those subinterfaces that you created will need to have an ip address assigned to them. So to make it easy, we will make subinterface 0.1 192.168.1.1 and then 0.100 192.168.100.1 and with 0.200 192.168.200.1. Now for the dhcp, you will need to decide whether you want your router to hand out the ip's or if you already have a dhcp server to do this. If you already have your own dhcp server, you simply add ip helper x.x.x.x (where x.x is your dhcp ip address) Your switch should have the ability assign it an IP address as well. Just give it any other address on the vlan 1 network...ill use 192.168.1.2. It should also have a default gateway or default route option which you should put as 192.168.1.1 (your router vlan 1 address). from there just assign your switchports as access ports and then define them as vlan 100 or 200. Thats the short version....it should get you started.
 
OK, all say it has no DHCP support, please explain why there are DHCP commands in the command set, the only one I have found was Renew/release. I do know what R/R is, but what is it referring to on a 2980G-A?
 
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