| [Windows] Router not giving out IP addresses I have a new Netgear WNDR3700v3 running behind a Comcast business gateway. The Comcast modem is in bridge mode, not handing out private IP addresses, and we have two static IPs from Comcast.
So here's the issue: As long as a computer (or other device) has a static private IP (10.1.10.x) manually assigned, it's good to go. But if set it to obtain its IP, etc., automatically, it doesn't get one and can't connect to the Internet.
Yes, DHCP is turned on in the router (it's turned off in the modem, as I mentioned). It's set to hand out IPs at 100 and above, and all the static private IPs are 99 and below.
Netgear support has been less than useless; they can't seem to understand what I'm asking them.
Any ideas? |
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bdnhsv
join:2012-01-20
Huntsville, AL | Are you clearing the ARP cache in the router or rebooting the router after setting it to provide dhcp? also are you rebooting the pc's after changing them to dhcp? |
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| reply to tmccartney
When the clients are set to DHCP, what exactly does their configuration ultimately look like (i.e., the results of ipconfig)? Is it blank? Is it some unexpected foreign IP address? Is it 169.254.x.x? |
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| reply to tmccartney
Second eibgrad's comments of checking what IP address (if any) your computers are drawing when using DHCP.
Are you configuring your internal LAN as a 10.x.x.x address range?
Regards |
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| reply to tmccartney
What is the routers gateway address on the modem side?
As an example:
You can run into weird issues if you are using a Netgear 7550 router as your dsl modem and bridging it to a router.
Because the modem only uses 192.168.254.254 as the downstream gateway you cannot allow the router to assign 192.168.x.x to those it is providing nat and dhcp services to. You have to use 10.1.X.X address instead.
I suspect your modem is doing the same thing. See if you can get to use 10.1.x.x address instead so through your router can use 192.168 etc.
Otherwise you will have to go with 10.1.x.x for the machines on your network. |
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| reply to tmccartney
i have a Comcast business gateway (cable) at 10.1.10.1 with disabled DHCP that plugs directly into my sonicwall wan port. the lan port of my sonicwall plugs into my network switch. the sonicwall also has DHCP disabled. my server has a DHCP server that hands out 192.0.0.x addresses to all devices.
i dont have any issues with my equipment from Comcast once i disabled DHCP (i know i rebooted my Comcast equipment after i made changes).
to the OP, i can check settings if you have any questions on what the Comcast gateway should look like. |
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1 edit | reply to tmccartney
The router reboots itself every time there's a configuration change. As for the PCs, I usually do an ipconfig release and renew from the command line when I change their configuration.
reply to eibgrad
Re: [Windows] Router not giving out IP addresses
Yep - it gets a 169.254 address. I'd never seen anything like that. |
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| reply to eibgrad
Yep - it gets a 169.254 address. I'd never seen anything like that. |
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| Yep I know, very backwards I think. |
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| reply to tomdlgns
Your configuration sounds a lot like mine except for the router having DHCP disabled. A colleague of mine who does IT at a different agency also suggested using a computer to hand out addresses.
Aranarth, you asked "What is the routers gateway address on the modem side?" In the router config, the router's public IP address is 173.164.(redacted).(redacted), and the gateway IP address (the same address assigned to the modem) is one number off from that. Those are the two static IPs Comcast assigned to us. Subnet mask is 255.255.255.252.
BTW, sorry I'm not doing a better job of replying. Not used to this forum software. |
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| reply to tmccartney
the 169.254 address is the IP assigned from MS/OS stating that there is an error somewhere.
do you need me to confirm any settings in my comcast gateway? i have the same ISP/gateway setup as you. |
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| That would be great, Tom - I'd appreciate it. |
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| ok, what settings would you like me to check?
you can give me tab names or take a screen shot of what you would like to check. |
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| On the Comcast gateway, there's not much there, but I guess under Feature Settings | LAN | IP Setup, I'd be interested in what you have. |
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| ip address- 10.1.10.1
sub- 255.255.255.0
domain suffix- wp.comcast.net
enable LAN dhcp is NOT checked
assign DNS is set to manual and i have the comcast DNS servers in there. no sense in typing them out since it doesn't really matter what those are. |
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| reply to tmccartney
what is your router DHCP range at? i have seen networks with 60 computers have a dhcp range of 50, that will cause some issues when it is time to grab a new address.
can you disable DHCP in the device you are using now and connect a cheap router to the switch and see if that has any trouble handing out IPs? |
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| Our network is pretty small, so that shouldn't be a problem. Router is set to hand out IPs from .100 to .254, and static IPs are all assigned at 99 and below.
I don't have another router on hand, but I'll try that. I'll also play around with that range. |
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| Weirdly, I changed the range of IPs the router is handing out, and it worked! But changing the range BACK didn't cause failure, so I don't know that it's the problem. The good news is that it seems to be working at the moment, but it will be very BAD news if this turns out to be an intermittent thing that I can't reproduce reliably. Thanks for everyone's help. |
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| said by tmccartney:Weirdly, I changed the range of IPs the router is handing out, and it worked! But changing the range BACK didn't cause failure, so I don't know that it's the problem. The good news is that it seems to be working at the moment, but it will be very BAD news if this turns out to be an intermittent thing that I can't reproduce reliably. Thanks for everyone's help.
believe it or not, i was going to recommend changing the dhcp range just to get the router to notice a change/update in settings, maybe it didnt like the setting last time it was applied. however, it looks like you tried that and had good luck.
glad to hear that it is working. |
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