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Regular Contributor
Posts: 25
Registered: ‎10-07-2004

help: router won't get ip address from cable modem?

Wall => Cable Modem => Router => desktop with NIC, wireless laptop, VOIP

Cable Modem = Model 5041 Zoom USB Ethernet (using Ethernet)
Router = Netgear WGR614v1 firmware 1126 or 1400 (read below)
Operating System: XP SP2 Home Edition

Okay, here we go.

I’ve had this setup for quite some time with Comcast while in Foster City, CA, and now in Atlanta, GA.

Last month I had what appears to be a hard drive boot issue after upgrading to SP2. Anyway, once I was able to get my computer up and running again. My once pretty stable internet home network system lost internet connectivity.

The first time around I was able to determine that my router was not getting an ip address assigned from the cable modem. Many newsgroups indicate that one solution is to clone my desktop’s MAC address. I did that and internet connection worked again. What I couldn’t figure out is why it worked prior to cloning the MAC address; I used the default MAC address of the router and had no problems for more than 6 months in Atlanta.

Oh well, I didn’t worry about it since everything seemed to work again.

Now, Tuesday, March 22nd, my hard drive failed again! It seems I really didn’t fix it the first time around. In any case, I’ve got the computer booting up and running again with two bootable hard drives now. But I’ve lost my internet connection. Similar to before, it appears that my router can’t get an ip address from the modem. I’m guessing this because plugging any of my computers directly to the cable modem gets me full internet connectivity. When I return the router into the setup, my home network is just fine. Both computers can talk to each other, share files and print and are using router assigned ip addresses. I just can’t get any internet connectivity thru the router.

I’ve tried the following solutions:

1) cycling modem, router and the computers
2) cloning the MAC address and then turning that off
3) changing firmware for the router

I’d appreciate any new suggestions. There was a whole other thread in January that didn’t seem to ever be resolved and it sounds like what I am experiencing. http://forums.comcast.net/thread.jspa?threadID=32153&start=0&tstart=0

Thanks in advance,
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

Anon993936 said:
Now, Tuesday, March 22nd, my hard drive failed again! It seems I really didn’t fix it the first time around. In any case, I’ve got the computer booting up and running again with two bootable hard drives now. But I’ve lost my internet connection. Similar to before, it appears that my router can’t get an ip address from the modem

This doesn't make any sense at all. Your computer having a hard drive problem in no way, shape, or form has any effect on your router's ability to get a DHCP lease form Comcast. They are entirely disjoint operations. The fact that both problems happen at the same time indicates they may have the same root cause and I'm thinking power surge.

What is the precise setup on the router? Have you tried reseting it to factory defaults and then redoing the wireless security setup? Factory defaults on most routers work on Comcast with no modifications.

When you power cycle the cable modem do you remove the ethernet and power cables and leave them disconnected for at least 1/2 hour? Some modems have large capacitors and persistent memory for their CPE device table, which needs to be wiped. I'd recommned seeing if the cable modem has a reset procedure. After it's been reset and off for quite awhile, do this:

1. Connect the power cord only. Let the modem connect to Comcast before continuing.

2. Plug the ethernet cable from the router's WAN port into the ethernet port on the cable modem.

3. Power up the router and let it initialize (about 30 seconds).

4. Power up one and only one PC connected via ethernet to one of the LAN ports on the router.

Do things now work? Then boot the other systems. If things don't work, give us the following information:

a) "ipconfig /all" output on the ethernet connected PC.
b) complete router setup and status information (all of it, not just a piece here and there)
c) modem status at http://192.168.100.1 if your cable modem supports this. All the status pages, not just the default one which comes up, include signal status, connected CPE devices, error log, system information, etc.
d) front panel lights on all the devices (router, cable modem, PC ethernet adapter)
e) the PC's ethernet adapter device settings from the Device Manager
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

Thanks. I realize the HDD failure probably has nothing to do with the router status. I just chose to point it out as an unusual coincidence and most likely someone will know more about it than I. What I meant by not having fixed the problem the first time, I was referring to the HDD, not the router. Sorry for the confusion. I'm still glowing from being able to recover my HDD and all its data. That could have been a disaster.

So, back to the router, in terms of the power cycling, I will try it again as you suggested. The first time I lost connectivity a month ago, power cycling just as you described didn't work. But that being said, it doesn't mean it won't work this time around. I will report back later.
New Visitor
Posts: 1
Registered: ‎03-24-2005

Re: help: router won't get ip address from cable modem?

hello, i had a similar problem with my netgear router. It would not work until the host and domain info that says "might be required" is filled in. I do not remember what goes in these fields but i do remember i found out by looking in the help. They gave examples and i used that.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

These fields are NOT required on Comcast. They are not used. So unless there is some firmware problem on that router, you should leave them blank.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

If it doesn't work, post back with the information I requested and we can start narrowing the problem down.
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

Okay. The Power Cycle didn't work, so I've gathered what I can. I was unable to get:

1) modem status. I’m not sure how to do that and zoom's website wasn't helpful for my model.

2) PC Ethernet adaptor device settings. I went to the device manager and clicked on my card and the properties button. there is a ton of stuff on several tabs, and i wasn't sure how to efficiently convey the info.

So her it goes. I did one ipconfig /all with the MODEM>ROUTER>DESKTOP setup

Microsoft Windows XP
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\ >ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : desktop
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : homenet

Ethernet adapter Local Area Connection 2:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : WAN Network Driver
Physical Address. . . . . . . . . : 00-03-8A-AA-AA-AA
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Autoconfiguration IP Address. . . : 169.254.101.152
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : homenet
Description . . . . . . . . . . . : Intel(R) PRO/100 VM Network Connection
Physical Address. . . . . . . . . : 00-02-AB-BB-BB-BB
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.0.2
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 192.168.0.1
Lease Obtained. . . . . . . . . . : Thursday, March 24, 2005 11:28:16 PM

Lease Expires . . . . . . . . . . : Sunday, March 27, 2005 11:28:16 PM

C:\Documents and Settings\ >


this ipconfig is straight MODEM>DESKTOP

Microsoft Windows XP
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\ >ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : desktop
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : hsd1.ga.comcast.net.

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : hsd1.ga.comcast.net.
Description . . . . . . . . . . . : Intel(R) PRO/100 VM Network Connecti
on
Physical Address. . . . . . . . . : 00-02-AX-XX-XX-XX
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 66.56.10.99
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 66.56.10.1
DHCP Server . . . . . . . . . . . : 68.87.68.13
DNS Servers . . . . . . . . . . . : 68.87.64.196
68.87.66.196
Lease Obtained. . . . . . . . . . : Thursday, March 24, 2005 10:37:43 PM

Lease Expires . . . . . . . . . . : Monday, March 28, 2005 10:37:43 PM

Ethernet adapter Local Area Connection 2:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : WAN Network Driver
Physical Address. . . . . . . . . : 00-03-8Y-YY-YY-YY
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Autoconfiguration IP Address. . . : 169.254.101.152
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

ROUTER SETUP

Account Name: desktop
Domain Name : homenet

internet ip address: get dynamically from isp
dns address: get automatically from isp

router MAC address: use computer mac address (I’ve tried using router MAC address too)

wireless network
SSID: wirelessnet
Region: USA
Channel: 11
Mode: g and b
packet burst mode: enabled

security options: disabled

Router Status
acct name: desktop
firmware: version 1.40 feb 18 2004

internet port
MAC address: 00:02:aA:AA:AA:AA "matches desktop"
IP address: "is blank"
DHCP: DHCP Client
IP Subnet mask: 0.0.0.0
Domain Server: "is blank"

LAN Port
MAC address: 00:09:5C:CC:CC:CC
IP Address: 192.168.0.1
DHCP: on
IP Subnet mask: 255.255.255.0

Connection Status
IP Address: 0.0.0.0
Subnet Mask: 0.0.0.0
Default Gateway: 0.0.0.0
DHCP Server: 0.0.0.0
DNS Server: 0.0.0.0
Lease Obtained: 0 days, 0 hrs, 0 min
Lease Expires: 0 days, 0 hrs, 0 min

cable modem lights

1) power = solid green
2) sync = solid green
3) activity = blinks once every 6-10 secs. Normally it blinks all the time as the router (which is not connected to the desktop) communicates with the modem.
4) 10/100 = solid green
5) USB = off

router lights

1) power = solid greem
2) internet = blinks irregularly every second or two
3) wireless = solid green. normally blinks during wireless activity, but shouldn't right now as i don't have any wireless devices connecting while troubleshooting this problem.
4) 1 = solid green, but blinks when my desktop communicates with the router.

That's what I've got. Again, thanks for everyone's efforts.

-a
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

Well, you have a definite problem between the cable modem and hte router, not sure what at this point. You have the very oldest version of the WGR614 and you're running the latest firmware (1.40) inspite of the fact that it's over a year old.

Your router config is wrong in a couple of areas, but it shouldn't make a difference, but you never know. You should always do a factory reset after updating firmware to clean up the configuration. I'd do the following in order to clean it up:

1. Reset the router to factory defaults. Consult your manual for how to do this. DO NOT MAKE ANY FURTHER CHANGES TO THE ROUTER. Do not MAC clone, setup account or domain name, etc.

2. Power everything down and let everything off for 5 minutes.

3. Boot the cable modem and let it connect to Comcast before continuing.

4. Boot the router and let it initialize.

5. Boot a wired PC.

What is the router configuration now? IS the problem the same?

If it is, I'd say either you either have a router/modem incompatability, or there's something wrong with the router's firwmare or hardware on the Internet interface. Simple thing to do is rent a cable modem from Comcast for a month and see if the same problem persists. Just realize that any time you change the device connected to the modem, you MUST reboot the modem or it won't work. If the new modem doesn't solve the issue, I'd replace the router with a newer model (you're 4 hardware versions back on that model), and I'd recommend a Linksys WRT54G.
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

Thanks for the input.

I think what confuses alot of ppl in the forums is when something worked fine for months and even years, and then it doesn't. That’s the case with this router. I’d hate to throw out a perfectly good piece of equipment because I can't figure out how to configure it properly... of course, it may have finally died. I’m going to borrow some other routers and test them out before I send the Netgear packing.

I’ll post again on what I eventually do.

-a
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

If it worked this way for a long time and now doesn't, that's an indication that it broke. Hardware does that. It's annoying, but a fact of life.

If you can borrow another known working router, that's a good test.
New Visitor
Posts: 9
Registered: ‎09-22-2004

Re: help: router won't get ip address from cable modem?

I've got nearly the same problem: an RP614v2 Netgear router that, as of this morning, can't get a DHCP address. My Mac can get one fine. Oh, well, router's broke - except that, if I take the Mac's MAC address and the IP address it was served, and manually configure the Netgear with those (along with the netmask, gateway, DNS yadda yadda), everything works fine again. Except of course I'm shafted when Comcast changes my IP address. This proves, though, that the hardware's working fine.

What the heck???

BTW I did try this: change MAC address on Netgear to MAC address of Macintosh, try again to get DHCP address, to see if for some reason they'd blocked the Netgear's native MAC address. Uh-uh. It won't get a DHCP address no matter what Mac address it has.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

This usually means that there's something wrong with the router''s firmware, such that it's DHCP client is not longer talking properly to Comcast. Probably something changed on Comcast's side with how they handle the DHCP conversation and the router can't handle the change. Please note that this is usually a ROUTER problem and not a Comcast issue. Many want to take the easy way out and blame Comcast here, but the fact is that the router's DHCP client is deficient in some way. Usually a firware upgrade and router reset will fix this issue (assuming the router manufacturer is on the ball and hte router is not an older model).
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

I'm in agreement with both Baric and Anon---817, I think Comcast has changed some kind of communication setting, but whatever it has changed, should be compatible with current router drivers and firmware.

Unfortunately for us, the last time Netgear issued any firmware upgrades to our versions of the WGR614's was quite some time ago. Mind you, I'm running on a beta version of my firmware and that's over a year old.

This is not specific to Netgear either. I've seen threads for at least Linksys where early adopters are annoyed because when they bought their routers, the firm indicated that they'd support those routers with upgrades. i.e. WEP to WPA security features.

In any case, I don't expect to get much support from my manufacturer as it's moved on to other products.

Another experience to illustrate my point is when my router also went a little crazy when I upgraded my XP to SP2. Microsoft indicated any driver issues that arise could possibly be solved by downloading your manufacturer’s SP2 compatible driver. How many manufacturers do you think actually have done that?

Anyway, I will report my progress…
New Visitor
Posts: 1
Registered: ‎03-23-2005

Re: help: router won't get ip address from cable modem?

I was having the same problem with my Linksys WRT54G not obtaining an ip address after using it with DSL for months, this is how I fixed it:
1. Go into the web gui, usally at ip 192.168.1.1, and go to the status tab.
2. Click DHCP Release button.
3. Power Cycle the router before clicking on renew (this was the key step.)
4. Click DHCP Renew button.

I hope this helps.
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

Eureka!

I've got it working.

Here's what I had to do. In my router, I've normally had my "Acct Name" and my "Domain name" filled out with values to support my home network. See the above posts on my router settings.

On my last factory "reset" suggested by Baric, I noticed that the Acct Name and Domain Name still had my old values. Not sure why it didn't reset to blank. Perhaps the latest firmware messes up the factory resets as it now sees values that it previously had no settings for. In any case, I just removed both the Acct and Domain values and now the router works. I didn't even need to power cycle or anything.

Of course, I've got some issues with my home network now, but we'll take things one step at a time.

Thanks again for all who posted.
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

oh, one more thing if i wasn't clear. i essentially have the exact same router settings as i posted with the exception of the acct and domain name values are blank. i.e. i have MAC cloning on. i just did a test turning MAC cloning off and got 0.0.0.0 ip address assigned to my router.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

You can't turn off MAC cloning without also power cycling the modem. Any change to the MAC address of the attached device requireds the modem be reset.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

Hmmm...that's very strange. A factory reset is supposed tp get rid of settings just like this. I have no explanation for this behavior. Not to mention those fields should have no effect on anything. But obviously not. Glad you working now.

Next time, get a Linksys :smileyhappy:
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

Your connection type is set improperly. DSL requires different settings. Rsset the router to factory defaults and it will work, the WRT54G works out of the box on Comcast.
New Visitor
Posts: 9
Registered: ‎09-22-2004

Re: help: router won't get ip address from cable modem?

My own problems continue. A factory reset on my RP614v2 Netgear router still won't allow it to get a lease. Setting its WAN MAC address to that of my Macintosh still won't get a lease, so it's not as if Comcast has flagged me. Their online chat support guy says there are no flags on my account anyway.

I'm just totally baffled. The DHCP request from my Macintosh and from my Netgear should look identical. But one succeeds and one doesn't.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

Do you have an account or domain name specified int he router settings like the other poster? If so, try getting rid of them, it might be some sort of Netgear bug.

As for the DHCP request being identical, I bet they are different, but more likely the response coming back from Comcast is what the router is choking on. If you a have old firware, upgrade. If your router has the capability, set the speed of the WAN link at 10Mbps and half duplex.

And stop fiddling with the MAC setting, leave it one way or the other (it doesn't matter which one you choose) and power cycle your modem. Comcast could care less what it is, just that it doesn't change, the modem with stop working if it does. You're just confusing the issue.
New Visitor
Posts: 9
Registered: ‎09-22-2004

Re: help: router won't get ip address from cable modem?

Tried all of those. No soap.

Time to give up and buy a new router.
Networking Expert
Baric
Posts: 24,238
Registered: ‎07-28-2003

Re: help: router won't get ip address from cable modem?

I highly recommend the Linksys WRT54G.
New Visitor
Posts: 1
Registered: ‎03-26-2005

Re: help: router won't get ip address from cable modem?

I've had the same problem here in Michigan. The problem is you need a new modem. I'm using a D-Link router and my connection would just quit. I can walk away and return later and my connection will be back. I had a service tech come to my house and said this is a common problem with a bad modem. Get a new modem from Comcast and you probably won't have the problem anymore. Of course you don't know if you'll get a better modem this time either so ask for a new one.
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

Here is another solution that works for me. My router still has problems communicating with the cable modem, so I changed my physical connections slightly as follows:

Wall -> Cable Modem -> VOIP Modem -> Router -> Desktop, Wireless Laptop, Ethernet Bridge to PS2

My router apparently has no problem communicating with the VOIP modem and the VOIP modem has no problem communicating with the cable modem.

-a
Regular Contributor
Posts: 67
Registered: ‎10-16-2003

Re: help: router won't get ip address from cable modem?

For what it's worth, I have a new SB5200, or is it 5100, Motorola.

My router is at least a year old, a Linksys wireless.

I started having these same problems about 2 months ago, here in South coastal NJ.

Now it started again. This weekend has been absoultely horrendous.

At this point, I've had to reboot the laptop, my only unit, a Fujitsu centrino lifebook, at least 3 times. Twice connected to the modem.

All the lights on the modem are there, and are stable.

Same with the Router.

I'm up and running now.

The only thing that's been unusual around here is rain!

Rain, rain and more rain.

We have underground wiring here, a mostly wooded, rural area.

Me thinks, maybe, the lines are getting soaked.

All I know is, I'm fed up, but too far away for DSL, and too many tress for SAT.
Recognized Contributor
AlisMan
Posts: 1,210
Registered: ‎10-31-2004

Re: help: router won't get ip address from cable modem?

> MAC address: 00:09:5C:CC:CC:CC

What is it about MAC addresses that makes people want to hide them?? Do you think we can hack you if we know your MAC address or something? Do you think it gives us information about where you live? Do you think it reveals family secrets?

This is my MAC address, I challenge someone to try and hack me or something. At least explain to me why people want to hide their MAC address.

00-06-5B-49-68-D9
New Visitor
Posts: 1
Registered: ‎03-29-2005

Re: help: router won't get ip address from cable modem?

How do you get an IP,router, address? I have an RCA modem and network hub(modelnh1005-wm). also the DNS addressand secondary DNS address.
New Visitor
Posts: 9
Registered: ‎09-22-2004

Re: help: router won't get ip address from cable modem?

Well, I said it was time to buy a new router, and I did - two of them, to be exact.

My old router was a Netgear RP614v2. Because they were dirt cheap from NewEgg, I bought both a Netgear RP614v3, in case a new revision would help or the hardware had somehow died on the old one, and also a D-Link DI-604 router just to hedge my bets. Good thing I did.

The RP614v3, which (as well as the RP614v2) was running the latest firmware, also failed to obtain a DHCP lease from Comcast. However, the D-Link DI-604 obtained one without a problem. So, I'm back on the air, though I did have to change the configuration of my printer because the D-Link insists on using net 192.168.0 and can't be reconfigured to 192.168.1 as both Netgear and Linksys can do. (I didn't go with Linksys because I used to own a BEFSR41. It had a hardware failure, and now the one I bought my girlfriend is getting red error lights once every week or two. Fooey.)

I chalk this up to the recent speed increase. Apparently the DOCSIS file they sent to my cable modem tweaked some settings in such a way that Netgear firmware can't understand the lease process somehow. I'm betting everyone in LA with a Netgear router is now SoL.

Fooey. Hello D-Link.
Regular Contributor
Posts: 25
Registered: ‎10-07-2004

Re: help: router won't get ip address from cable modem?

Alisman:

Please see the following link.

http://www.computerworld.com/mobiletopics/mobile/story/0,10801,83152,00.html

The threat is not having your systems hacked, but rather someone impersonating your equipment on hacking outside systems.