Networks

Ask something
Question Locked

One DHCP on multiple VLANs

0 helpful
10 replies

by rafal 1 view

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

I'm running a network on a Netgear 7352s Managed L3 Switch. The problem I'm having is as follows:
I have separate VLANS for DATA and VoIP, the DHCP server works fine on the default VLAN but on all the others it does not. Here is a string of commands I used to set the DHCP and VoIP VLAN up.

#VLAN DATABASE
#VLAN 2
#VLAN NAME VoIP
#VLAN ROUTING 2
#VLAN MAKESTATIC
#EXIT

#CONFIGURE
#IP DHCP POOL pool1
#NETWORK 192.168.16.0 255.255.240.0
#DEFAULT-ROUTER 192.168.16.1
#EXIT

#INTERFACE VLAN 2
#IP ADDRESS 192.168.16.1 255.255.240.0
#EXIT

#SERVICE DHCP

I'll add that the default VLAN is setup under 192.168.0.0 network not 192.168.16.0

If the device is plugged into the port connected to default VLAN it gets an IP from DHCP without a problem, if its on the VoIP VLAN it gets no response.

Anyone see what I'm doing wrong?

10 replies

by rafal

The VoIP provider isn't really relevant. I'm using Cisco 7940 series IP phones if that helps. Right now I'm just trying for them to receive an IP before I actually put this on the main network.

by cg it

by default communications between vlans is blocked. you need to implement VTP server and VTP clients

by rafal

What about IP HELPER?

I know Cisco switches have a way of setting this up.

So far what I've managed to acomplish is to have data on VLAN1 and voice on VLAN2 the DHCP is on the DEFAULT VLAN. The Problem is now the DHCP uses the same IP POOL for all devices. This is still not right.

by cg it

so, what you want is for DHCP to provide addressing for each VLAN and for each VLAN to have it's own subnet range?

by rafal

Correct.
I'm looking to use a C class network subneted as a B class.
192.168.0.0 - 192.168.15.254 (Default VLAN)
192.168.16.0 - 192.168.31.254 (VLAN 1)
192.168.32.0 - 192.168.47.254 (VLAN 2)
.
.
etc.

The way I'm running it now I have single devices connected to the VLAN ports, and I'm starting to think that they should be routers hence the problem. You think this could be the issue?

by rafal

I'm trying to use the switch DHCP feature not a Windows based DHCP server?

by cg it

DHCP is DHCP.

Send a PM to George OU or Dave Davis. Ask them or check TechRepublic white papers or articles on "how to configure DHCP on Cisco Switches" or see Cisco.com

This discussion is closed to new replies.