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#67668 by 5107441532
Wed Oct 27, 2010 12:53 pm
My "Modem" is a box that runs DD-WRT and combines the functions of Modem, Router and WiFi Access point. The LAN side of the Router connects to a Cisco hub, that then feeds CAT-5 Cables that run to every room. Except for occasional free-roaming devices like the iPad, iPhone or Notebook, I rarely use the Wifi side. Most "Real Computers" are hardwired to the hub.

So I insert the Ooma between the DD-WRT box and the hub. All works well except for one thing. Ooma insists on being the DHCP server for my LAN, and hands out IP addresses that randomly conflict with those handed out by the DD-WRT. There seems to be no way to disable the serving of DHCP addresses by Ooma.

Now days most (well, every one I know of) DHCP servers have ways to exclude devices, always hand the same IP address to the same Mac Address (i.e. My Tivo is always to be given 192.168.1.101) etc. I would have no great objection to letting Ooma be the DHCP server, and turn it off in DD-WRT. Except that the DHCP implementation of Ooma is sadly crippled. It won't let me turn it off (at least I cannot find any switch to disable it) and it won't let me assign names and Mac Addresses to specific IP Addresses. It just hands out random IP addresses from whatever pool it knows about (and won't let me set that pool to zero) to any device that comes along. This means I cannot rely on any particular device being at any address. I could set some devices to static addresses and use them this way, but it is a pain to change every device (Tivo particularly is a pain). Further, the free roaming devices, such as iPad, etc, need to get their IP addresses from the DD-WRT box in any case, since it has the WiFi radio. So I really need DD-WRT to be the DHCP server.

So, unless I can, and quickly, find a way to turn off the DHCP of the Ooma and allow the DD-WRT Router to do the job without conflict from Ooma, then I must return ooma to the store and forget the VoiP service.

I tried setting the Ooma to a different address space, but that means I cannot get to it from the LAN, and it then hands out bogus addresses to other devices causing them to disappear from the LAN. I tried setting the DHCP range to a different space, or to a zero host count. Nothing worked. It just keeps on handing out useless, bogus and conflicting addresses.

Does anyone know a way to shut off the Ooma DHCP server? Unless I solve this quickly, I am going to give it up. ooma Tech support has not been especially helpful thus far...

Thanks,
Nathan
#67669 by murphy
Wed Oct 27, 2010 1:17 pm
Connect Ooma to your system exactly the same way that you connect a hardwired computer.
Leave it's home port empty.
#67671 by 5107441532
Wed Oct 27, 2010 1:49 pm
Thanks for the suggestion. I thought of that, but it has some drawbacks.

(1) It seems that the Ooma internal web server does not listen to 80 on the network port. Thus it is impossible to connect to the unit from the LAN.

(2) Since the traffic from the computers does not pass thru the Ooma so it can prioritize traffic, voice quality suffers.

Perhaps QoS settings in the DD-WRT can mitigate some of the effects of #2, I will look at that. But is there another path into Ooma's web server?

It would be nice if they just provided an option to turn off DHCP....

Thanks,
Nathan
#67672 by highq
Wed Oct 27, 2010 2:10 pm
Nathan, using your phone number as your login name will only attract maggots, of the spamming variety. Do call Ooma customer service and get it changed.
#67674 by 5107441532
Wed Oct 27, 2010 2:17 pm
Yeah, a stupid brain fart. I knew better. But I am inches away from returning the Ooma anyway because I can't make it play nicely in my network. So I will probably cancel the whole shebang momentarily.

Thanks,
Nathan
#67682 by murphy
Wed Oct 27, 2010 4:23 pm
5107441532 wrote:(1) It seems that the Ooma internal web server does not listen to 80 on the network port. Thus it is impossible to connect to the unit from the LAN.

Once the Ooma box is configured there is little need to connect to it again.
That said, connect a computer to the Home port and forward port 80 to the IP address of the Home port.
You can then connect to the configuration page from the WAN side by connecting to the IP address that your router has assigned to the Ooma's WAN (Internet) port. If you ever put the Ooma back in front of your router this forward must be removed because it opens the Ooma up to the world.
#67715 by nn5i
Thu Oct 28, 2010 5:30 am
There's no way to disable Ooma's DHCP, but you can port-forward in order to get to Ooma from your LAN even when it's behind the router, and use the QoS in DD-WRT instead of that in Ooma.

Does the busy traffic on your LAN consist of PCs talking to each other, or PCs talking to the Internet? If they're talking to each other, then replacing the hub with a switch might alleviate the problem. When two devices on a hub are talking, every device is busy, and the hub processes only one communication at a time. When two devices on a switch are talking, only those two devices are busy, and the switch can process simultaneous communications between many pairs of devices at a time. So, if your PCs are talking to each other, on a hub they will slow down the Ooma's talking with the Internet, but on a switch they won't. I run DD-WRT on many devices in my LAN, but there are no hubs -- only switches.

But if the PCs are talking to the Internet instead of to each other, of course they will interfere with the Ooma's need to talk to the Internet, even on a switch.

Incidentally, what device are you running with DD-WRT? I had thought that DD-WRT could run only on routers, not on any device that is also a modem.
#67810 by Nat Ray
Fri Oct 29, 2010 6:51 am
1.) From Ooma's 'Network' menu insure 'Use Built in' is selected for the Modem Port's MAC Address . . . Write ths address down, you will need it later . . .

2.) From Ooma's 'Advanced' menu under 'Port Forwarding' add a rule to forward port 80 TCP to 172.27.35.1

3.) Access your router's web interface, under DHCP reserve an IP Address for Ooma using the MAC Address you obtained in step 1

4.) From any computer on your LAN access Ooma using the IP Address you reserved for Ooma via your router's DHCP service, i.e. http://198.164.xxx.xxx

Hope this helps . . .

Best regards,
Nat Ray :cool:
#67967 by sfhub
Sun Oct 31, 2010 6:29 pm
5107441532 wrote:Does anyone know a way to shut off the Ooma DHCP server? Unless I solve this quickly, I am going to give it up. ooma Tech support has not been especially helpful thus far...

This post gives info on an unofficial way to disable the DHCP server.
viewtopic.php?f=8&t=6253&p=44462#p44620

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