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davidgeeee

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Replacing an HP procurve switch with a Netgear switch with phone and data VLANS doesn't work.

I have a area where there is an HP procurve switch in place that works fine but is 10/100.  So I am tryning to replace it with a Netgear switch.  The computers on the network are plugged into the phones and the phones plug into the switch.  The computers and phones get DHCP address from the domain controller.  Phone get a 192.168.5.0 address and the computers get a 192.168.1.0 address.  I matched the vlans configuration on the Netgear switch as close as possible to the old HP switch.  

The problem is the phone will not get a address from the DHCP server.  What can I do to identify what might be the problem(s)?
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Michael Ortega
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Not sure what phones you have or how DHCP is setup, but typically if this is an automated procedure your switchports are trunked (the ones where the phones are plugged into, of course), native VLAN set for your data network, phones get DHCP address first on the data VLAN with vendor specific options to set the voice VLAN on the phone, the phones reboot on the new VLAN and get a new IP address from the DHCP server on the phone VLAN or if you have DHCP relaying configured on the voice VLAN they receive the IP address for the voice VLAN from the data networks DHCP server.

This is assuming a lot. Can you provide more information about your configuration? Where is/are your DHCP server(s)? Are there special DHCP options configured to set the VLAN on the phones or is the VLAN set on the phone manually?

MO
What type of handset?
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davidgeeee

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The Phones are Mitel.  They have a DHCP 128 mode selected and on the DHCP server there is a scope option 128 that points to 192.168.5.2 which is the phone server.  So, I guess, the phone server gives the IP address to the phones?
The data network is Vlan 1 and the Phones are Vlan 5.
What is assigning the VLAN to the phone though? Has someone manually set the VLAN? Either way, can you confirm the switchport setup? You need to set the native VLAN or PVID of the phone to the data network. In this case, if it's VLAN1, you most likely wouldn't have to change anything since that's the default VLAN. You do, however, need to set the switchport to TRUNK and allow VLAN's 1 and 5 through.

The handset needs to get it's VLAN association from somewhere. Either it has been manually configured on the handset or it's getting it through DHCP on VLAN1. The phone will never talk to the 192.168.5.2 server until it's set on VLAN5.

MO
The mitel phones assign the VLAN to the PCs. They embed a "micro switch".
The ports on your netgear switches must be able to handle packets for VLAN 1 and VLAN 5.
Not sure how this is named in Netgear's world. In Cisco's world, this is named "trunked" (but trunks in HP Procurve are different:
http://www.petenetlive.com/KB/Article/0000741.htm
).
Inter-vlan routing must be enabled on the switch/router
All the routers/switches (including the ones in the phones, if need be) must have a DHCP-relay in place so that DHCPDISCOVER packets sent by PCs/phones (that are not on the same subnet as the DHCP server) to broadcast addresses be forwarded to your DHCP server. If it was working with the ProCurve, no need to change anything on the phones I'd say (especially if the PCs and DHCP server are on the same subnet). However, the netgear switch must forward the DHCP broadcast packets sent on VLAN 5 to the DHCP server:
http://kb.netgear.com/app/answers/detail/a_id/21990/~/how-do-i-configure-a-dhcp-l3-relay-using-the-web-interface-on-my-managed-switch%3F
No need for inter-VLAN routing on the switch if your switch trunks to a router/firewall that has both VLAN interfaces on them. The router/firewall can forward traffic if you have that set appropriately.

The Mitel PBX is quite capable of being the DHCP server on VLAN5, so you might not need any DHCP relaying if the PBX is providing DHCP to the phones. Still the challenge is getting the phones onto VLAN5. Can you verify whether the phones have VLAN5 hardcoded on them or whether your DHCP server on VLAN1 is providing options to either assign the VLAN on the phone or pointing the phones to download a config file which will assign the VLAN?

Can you verify where DHCP is for VLAN5?
Can you tell us what make/model of Router/Firewall you have? Whatever your Netgear switch trunks to.

MO
The VLANS on the phones are not set to manual.  I have tried to manually set one phone to vlan 5 with no joy.

DCHP is setup on the domain controller and hands out addresses on the 192.168.1.0 network.  In the scope on the Server there is an option named 128 and the properties of the option are 192.168.5.2 which is the address of the phone server.  So, I assume the phone server hands out addresses on the 192.168.5.0 network.

All the ports that run to the phones/computers are 'tagged' in the Netgear switch, just as they were in the HP switch.  The PVID for the port that goes to the phone server is set to 5.  There is no comparable setting in the HP, so I don't know if that is right, just remember doing that on a similar install.
DHCP option 128 on the VLAN 1 is maybe useless if the phones are set to VLAN 5. If there is no DHCP relay, the "PC" DHCP server will not handle IP config to other VLANs.
If there is no scope for 192.168.5.x in your DHCP server, the phones (if they are on the .5 VLAN) are getting their IP config from somewhere else (Mitel Server is a good candidate!).
You could use a network sniffer (wireshark for instance) and filter on DHCP to try to see what is going on.
All your ports on the switch must be able to handle VLAN1 and 5. So they should be tagged at least for VLAN 5 (there is usually one VLAN that can stay untagged, and it is usually VLAN 1 that is also, usually, the management VLAN and that sometimes must stay untagged).
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Michael Ortega
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Figured it out.  The HP had a option called Helper Address that pointed to the Phone Server.  So I put static addresses on the p[hones and everything works.  If anyone know what the "Helper Address" does, it would be nice to know.

Thanks for you efforts, vivigatt and mgortega!!
Helper Address is a DHCP RELAY: The DHCPDISCOVER packets that are sent by the DHCP client nodes to local boradcast address are forwarded to all the IP addresses that are specified as helper address. This makes the client that are on another subnet able to get IPconfig from DHCP server located on a different subnet than they are.
Thanks for that vivagatt!