Confusion on where to point our VoIP VLANs ip-helper address

[JWHolm81891]

We are preparing to deploy a new system. I apologize if I don't word things correctly when trying to explain this, but honestly the most I've done on phones has been static configs and configuring port for VoIP VLANs. This rollout we have ESXi, VMs, we're configuring Option 150 on a server, and I need to figure out where to point the ip-helper for the VoIP VLANs (there are about 12 but they should all point to the same whatever will be acting as the DHCP server; my problem is I don't know what that is. On the last setup it was the CME on a Cisco 3925 router. (Sorry if I didn't word that correctly.) I was told specifically by the vendor (Presidio) that it would not point to the router this time, but she didn't know where to point it either. I'm looking for suggestions and your experience in helping me answer the question of where to direct my ip-helper on my VoIP VLAN configs. 

[Leonardo Santana]

Hi,

First of all, its a new deploy of a cisco collab system right?

The ip helper address will fit for your dhcp clients, so you need to point to the server that have your DHCP´s scopes configured.

Who is responsible for maintain the DHCP Server? They need to tell you this, where you need to point your helper address.

But if you need to know where you put the command ip helper address, generally at your L3 device, for example if your switch is responsible for the L3 of this VLAN, you configure under your interface vlan.

https://www.ciscopress.com/articles/article.asp?p=330807&seqNum=9

https://www.cisco.com/en/US/docs/ios/12_4t/ip_addr/configuration/guide/htdhcpre.html

[JWHolm81891]

Yes, it is a new deploy. Our Server Admin is supposed to be configuring the Option 150 on a server, but I know even he is confused about which server if acting like the TFTP server (and from what I've read that's where it has to be configured), so his confusion is just adding to my own. 

[Leonardo Santana]

Hi,

Its a windows DHCP?

Where are the VOIP DHCP Scopes configured?

If you go to a IP Phone or a computer you can check where they are requesting the IP Address.

This is mandatory for your deploy to work.

https://www.youtube.com/watch?v=6JCESszIg0A

[JWHolm81891]

Right, but where our current phone system is pulling IPs from is not where the new system will be pulling from. 

[JWHolm81891]

So, I spoke with our Server Admin and he said he configured the internal DHCP scope yesterday on a server, but the only time I've heard of internal DHCP scopes has been for wireless. Surely, I'm not pointing my helper at that server am I? 

[MHM Cisco World]

sorry for my late, 
but ip helper-address and op150 for tftp what is relate ?
can you elaborate ?

[JWHolm81891]

I don't understand your question....

[MHM Cisco World]

the seq is solution here
CDP first to assign VLAN for VoIP 
then DHCP <<- here you need ip helper address for DHCP server 
DHCP server send many info. include Op150 = TFTP IP  

so these Seq which step you confuse ?

[JWHolm81891]

I think the confusion on our end is what we're using as our DHCP server.

[MHM Cisco World]

ip helper must point to DHCP Server not to TFTP, that what I want to clear here. 
since the DHCP server is not in same VLAN of VoIP then you need IP helper and make VoIP get IP and Op150.