Vonage DHCP conflict - networking geniuses help!

Posts: 3 · New Forum Member Joined: Aug 26, 2004 Posts: 3

My Vonage connection keeps dropping out! I suspect DHCP problems.

OK, I got a Dell SC420 server running Windows Server 2003, set up as a DHCP server. My internet provider is Adelphia. Server's IP address is 192.168.0.111. Server has only one Ethernet port.

My internet connection comes into a D-Link DI-624 router, my Vonage adapter (Cisco 186) is attached to this router and I have the router set up to do DHCP but the subnet is only one address, 192.168.0.199. My server is connected to the router through a Dell 2324 switch. Router has IP of 192.168.0.1.

On Win Svr 2003 I have DHCP and DNS up and running, no problem. I have tried using a reserved address for the Vonage adapter but no luck, it drops out. If I disconnect my 2324 switch, effectively taking the server off internet, the adapter works.

Problem is this: my Vonage connection is unreliable ever since I added the Dell 2324 switch. I have to run DHCP on the server to parcel out addresses to other systems on my network but I fear there is a conflict somewhere.

Can anyone tell me what setup/configuration will yield more consistenly reliable connections?

With many, many thanks in advance,

-ak

Posts: 6 · New Forum Member Joined: Feb 19, 2005 Posts: 6

Having more than one DHCP server in a subnet is bad. I bet your phone adapter is periodically grabbing the one address that you're allowing the router to hand out.

I would do one of two things:

If you don't need any special Windows 2003 DHCP features, I would allow my router to be the DHCP server and lease out the addresses for the entire LAN. This is what I do on my home network, since my router is the only system on the LAN that is up 24/7.

If you need specific Windows 2003 features, or just like it better, then you should completely disable DHCP on the router. If your server isn't up 24/7, make sure your lease interval is long enough to cover the periods of downtime, or your attached equipment will lose the DHCP lease. Also, make sure you don't allow your DHCP server to try to lease the address 192.168.0.1 that is used by your router.

Those are some basic things to check. The most important thing will be to pick one system or the other to be your DHCP server.

Posts: 62 · Posted: Sat Feb 26, 2005 10:04 pm Post subject:

I agree, having more than one DHCP server on the same subnet handing out the same IP address pool only causes problems.
One possible solution, if you don't want to just make one or the other the sole DHCP server, is to set one of the DHCP servers with a small lease pool, 50 addresses, 192.168.0.125 to 192.168.0.150, and the other DHCP server with another small IP pool, 192.168.0.151 to 192.168.0.75. This way the PC's on your network would always be able to get an IP address whether your server is up or not, but they wouldn't be "grabbing" from each others pools.
Having said that, I don't believe this is the issue since you pull the Dell swich out, and presto, no problem. First thing I'd try to do is hard code the port configuration to either 10MB Full, or 100MB Full to ensure that you aren't seeing ports on the switch dropping in and out. If that doesn't work I'd check Dell's site to see if there is newer switch firmware/software as it appears the switch is at fault.
Hope this gives some direction...

Posts: 227 · Vonage Forum Master Joined: Dec 10, 2004 Posts: 227

He won't be able to hard code the ports as the 2324 is an unmanaged switch.

Posts: 62 · Posted: Sat Feb 26, 2005 11:09 pm Post subject:

You are very correct. I didn't even think about looking to see if it was unmanaged. Also doesn't appear to be any type of downloads for it either. That doesn't leave to many options.

Posts: 36 · Posted: Sat Feb 26, 2005 11:33 pm Post subject:

Jockstrap, having two DHCP servers on the same subnet is a problem. You're going to get conflicts which will cause network outages. This is what you're experiencing.

You could divide the netork using subnet masks, then run two DHCP servers on the same net. You'll have to understand the subnet metrics, network and broadcast address etc.

My advice would be to decide which device would divvy out the addresses, and allow only one to do so. If you have a dedicated server like mail, web etc you can veyr easily handle this task using the MS 2003 server and the DLINK router. You can do it with much less sophisticated equipment as well.

PM me if you need specific help.

Posts: 482 · Posted: Sun Feb 27, 2005 11:46 am Post subject:

I'm in a similar situation with several Compaq ProLiant servers running Small Business Server 2003 and Exchange 2K3, web servers, FTP, etc., but I just let my Vonage adapter handle DHCP. I've got it handing out 192.168.1.100-199 for TiVos, wireless, etc. and then my servers and workstations are on static IPs from 192.168.1.81-99. There's no reason at all to run DHCP on your Win2K3 server in that scenario.

Posts: 3 · New Forum Member Joined: Aug 26, 2004 Posts: 3

ToddlerTN wrote:

I'm in a similar situation with several Compaq ProLiant servers running Small Business Server 2003 and Exchange 2K3, web servers, FTP, etc., but I just let my Vonage adapter handle DHCP. I've got it handing out 192.168.1.100-199 for TiVos, wireless, etc. and then my servers and workstations are on static IPs from 192.168.1.81-99. There's no reason at all to run DHCP on your Win2K3 server in that scenario.

Thanks to all for your tips and suggestions. What I did was turn off the DHCP service in W2K3 Server and let my DLink adapter be the DHCP service for a 255.255.255.0 type subnet.

I never had two DHCP services running though - the DLink was only ever farming out one DHCP address, purely for the ATA 186, but it must have conflicted with the reservation I made in the original DHCP service on my server. Somewhere, somehow, W2K3 was overriding my settings and confusing the heck out of the poor ATA186!

Anyway, problem has gone away for now but I thank you all again.

Posts: 482 · Posted: Sun Feb 27, 2005 4:05 pm Post subject:

Glad you got it resolved. DHCP is a funny thing. I know you said the address ranges were seperate, but they way clients (in this case the Vonage adapter) find a DHCP server isn't that simple. Now that I understand more about your setup, if the only purpose for the DLink DHCP was the Vonage adapter, you could have just given it a static IP, turned off the DLink DHCP and left everything else unchanged. Although I don't remember you ever saying what other computers or devices you have in your network, either. Either way is probably six of one, half a dozen of another.