DHCP per Subnet

[Pigsfoot]

Hi,

We have an Avaya IP phone system running on the same network as a Windows 2008 AD. Due to running out of IP addresses we are looking to move the Avaya system onto a different Subnet but still be able to comminicate with the main Windows subnet..

What i'm not sure about is if we keep the Windows DHCP server running on the primary subnet will it oonly allocate IP addresses to that Subnet. We then want to enable the DHCP server on the phone system so we can issue IP addresses the the Avava handsets on it's own subnet.

I guess what i am asking for confirmation on is to make sure each DHCP servers will not issue IP addresses to the wrong subnet.

If anyone can confirm this it would be much appreciated.

Many Thanks

 

[cajuntank]

Create another scope on your DHCP server for the new subnet. Then on your layer3 switch or router (whatever you will use to make the networks talk to each other), put a "ip helper" statement to the DHCP server's address. You only will need to do this for the new subnet/VLAN you are creating for your phone network.

If you need further assistance, let me know what switch hardware you are using so I can be provide correct syntax.

 

[danramirez]

That is correct! make sure your L3 device has been programmed with the DHCP helper address. Depending on the manufacturer they may call it differently, some times it is called DHCP relay address or BootP relay address.

Make sure your L3 device has got an IP for every interface (Vlan/Subnet) and that every scope on your DHCP specify Option 3 (Router).

Also, if you are using VoIP make sure you specify correct options for L2 and DSCP priority.

This will work great, your DHCP will deliver IPs and options to the correct subnet/vlan.

Regards,

Daniel

http://www.hatkana.com

http://www.wtelecom.com