Different subnet

[Emrah Hatem]

Hi, I configured CX to our office.We have a server acting as a DHCP which is servicing the IP to the laptops.
And when we add CX,I could not communicate with IP phones.We have a problem with DCHP .

Our configuration on the network is ;

Controller IP : 172.20.3.140
Subnet mask : 255.255.255.0
gateway IP : 172.20.3.3 ( But IP of our real router is 192.168.0.1.Due to controller IP has different subnet,I could not give the same subnet to the gateway.)
primary DNS :172.20.3.4

[wiseguy]

A little more info is needed to understand why this is not working.
Subnet of the Phones? DHCP for the phones? Routing between the subnets?

[Chakara]

  The key here is what device is 172.20.3.3.  Is that the phone system?  If so it will not work that way.  You need a device that is capable is layer 3 routing in the middle of all this.  Typically a router or layer 3 switch.

-Chak

[Emrah Hatem]

Ok,let me explaing in detail ;

Our adsl modem in the office had 192.168.0.1,so we did not change it,then we added CX controller and configured as follows;

Controller IP : 172.20.3.140
Subnet mask : 255.255.255.0

And there is no device for 172.20.3.3,we added to the controller as modem,because we could not write 192.68.0.1 as router due to DIFFERENT SUBNET...

Ip phones are starting 172.20.3.142 to 172.20.3.179

Any idea ?

[ralph]

Looks to me like you've got 2 problems.
1 - You don't have a router in the network so you data network will never talk to your voice network.
2 - You've got DHCP set up incorrectly.

You didn't say how many phones you have but I'd suggest you turn off the DHCP on you server, re-IP your 3300 to the 192.168.0.x network and then use your Mitel to hand out DHCP.
I'd bet that will solve both problems.
Ralph

[Emrah Hatem]

Yes ralph you are totally right and I had thought your solution but did not intend to because I have to change so much things...I just thought it has maybe another solution.

[Chakara]

How many phones are on your system?  For small installations you can generally get away without a voice VLAN.  Move all the phone gear to the data network.  This goes against all best practice guidelines, but may work OK for you.

-Chak

[Emrah Hatem]

I will do like this ;
IP of all my laptop ( 192.168.0.x) are directed via DCHP server.I will not change it and set my MITEL IP as 192.168.0.x , another from the PC IP.Then I will let MITEL direct IP PHONES via its own DHCP again in the same subnet ( 192.168.0.x)

[ralph]

I'm with Chakara on this one.
If you don't have a lot of phones, I'd put everything on the same subnet.
Let the 3300 hand out DHCP for everything.
If you set up 2 vlans you will have to set up some options in your native vlan DHCP scope so the phones know will know where to look for the 3300 controller.

Ralph

[Emrah Hatem]

Ok but last thing I am considering when I read your last mail,you said that :
" Let the 3300 hand out DHCP for everything."
We have a DCHP server for laptops,will I disable DHCP server and let only 3300 make distribution of all IPs ( laptop and IP phones ) or will DHCP server hand out IP of laptops and 3300 hand out IP phones ?

[ralph]

If the phones are on the same subnet as the laptops, the phone system could hand out all DHCP address for both.
You could also use your DHCP server to hand out for both.  You'll need to set some options for the scope.
Best way to do that is to log into the 3300, go to the DHCP section and hit the help button.
You'll be able to find what options you need there.

Ralph

[Emrah Hatem]

Thanks ralph 

[brantn]

Yes you can set your DHCP Server to hand out the 125/128 options that Mitel Phones need view the help file there is also a Option 125 helper available through Mitel.