PCs refuse to renew IPs, ipconfig times out, network fails.

I have a small home network, and I will give you as many details as I can.  I have a Linksys BEFW11S4 rev. 4 router with the latest firmware and a Netopia DSL modem.  My ISP is EarthLink.  I have two desktops (WinXP Pro) connected via Ethernet.  I have a laptop (Win2k Pro) that connects on Wireless-B.  The laptop is my dad's work machine and uses VPN.  One desktop is sometimes taken out of the house for LAN parties etc, the other is never disconnected.  I have updated drivers for everything.
Problems (there are many)
 - Ideal situation: Start up PC, go online
 - Most common: I start up one PC, then another.  The second one can access the 'Net, but seems to have kicked the first one off.  They both show up in the DHCP Client table, but the PC that was first booted cannot access the internet.  I get the "Limited or No Connectivity" message.
 - Another common one: One PC is running, then my dad logs in (WEP 128) with his laptop.  He works for several hours.  I return, and my connection is gone!  I unplug the power cable from the router (this seems to fix all problems, temporarily at least) and get my connection.  Of course, I just killed my dad's, so he has to reconnect.  Repeat unplugging of router.  I've tried ipconfig, but I always get "Contact your DHCP server.  Request has timed out." message.  It seems I cannot have more than one computer on the network at a time.  This didn't used to be an issue, but after the laptop got reformatted twice, the problems began.  Keep in mind that these don't always happen, but keep coming back and won't go away!  I will provide additional details as I work through this issue.
Admiral_SovereignAsked:
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Fatal_ExceptionSystems EngineerCommented:
How are yoiu connecting your devices?  Are they all Wifi or just the laptop?  Have you cked the DHCP scopes to make sure you have enough IP addresses to hand out?  do you still have issues if the laptop is not connected?  Try to narrow this down a bit, so we can try to help, perhaps by hardwiring everything to see if it is a Wifi issue only.

FE
Admiral_SovereignAuthor Commented:
All are ethernet except the laptop.  The DHCP range starts at 192.168.1.100 and ends 50 addresses later, so I don't think that's an issue (if it is, tell me).  When the laptop is NOT connected, the two PCs still "kick" each other off.  I use one, someone switches to the other (the desktops are on a KVM switch), and when I switch back, my connection is gone.  I get the "Limited or no connectivity" warning.  ipconfig fails because, as I noted above, no matter what computer I'm on, I get  "Contact your DHCP server.  Request has timed out." error.  I think (based on my Googleing) that the computers are having issues renewing IPs...but I don't know how to fix that.  I also tried adjusting the MTU (by editing the XP registry) but that did nothing, in fact it made it worse!
Fatal_ExceptionSystems EngineerCommented:
(if it is, tell me).  >>  Nope, the scope should work fine.

The KVM switch should not be the issue here, but I would take it out of the picture, just in case.

The DHCP Lease time should be long enough that this should not be a problem, but...  MTU would not be the issue either..  I would suggest that it is within the router...  Let me think on this one a bit..  :)
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Admiral_SovereignAuthor Commented:
I do have fully upgraded firmware from Linksys...
Fatal_ExceptionSystems EngineerCommented:
Well, I downloaded the new firmware for one of my routers and it totally hosed my router.  Had to call Linksys and have them send me an old firmware version to get it back up and running...  Not that this is your issue, but want you to know that some firmware upgrades are not that nice!
Admiral_SovereignAuthor Commented:
My firmware upgrade reduced but did not eliminate the problems we experience with the rounter, I don't know if you have any other ideas...
Fatal_ExceptionSystems EngineerCommented:
I have to tell you, I don't...  It would be a little different if I was sitting at a client on your network, as solutions sometimes just make themselves evident through experience, and it could pop out at me if I was there.. but...  right now, I am running out of ideas here.  Is there a setting in the router where you can increase the lease time of the DHCP Offer Packet?
Admiral_SovereignAuthor Commented:
Yes, but it maxes out at two days, which I have it set to.  The speed/duplex is on auto, internet connection type is set to Obtain IP Automatically (should I use PPPoE?  My modem has a PPPoE light...)
Fatal_ExceptionSystems EngineerCommented:
Only on the router.   DSL uses either PPPoE or PPPoA for authentication, and must be enabled on the connecting device, just to get the connection.   When you use a router, then it must be setup on this.  There should also be a setting on the router that enables it to automatically reconnect when the connection drops, since DSL is not an 'always on' connection like Cable...

FE
Fatal_ExceptionSystems EngineerCommented:
Are you saying that you never setup the router for a PPPoE connection?  If not, then there is your problem!  :)
Admiral_SovereignAuthor Commented:
I have "Obtain an IP Automatically," "Static IP," "PPPoE," "RAS for SingTel," "PPTP," "Heart Beat Signal" and "L2TP."  Which one should I use?
Fatal_ExceptionSystems EngineerCommented:
PPPoE, if that is the authentication type your ISP is using...  and since it is on your modem, that is an indication...  You will need to input your username and password, which you should have received from your ISP when it was installed...

FE
Admiral_SovereignAuthor Commented:
I switched to PPPoE, and suddenly I got "Cannot find server" errors every time I tried to do anything...so I switched back to "Obtain an IP Automatically" and the connection worked again.  The reason I'm not talking to my ISP is that we did not order home networking from them, so they'd either refuse to help or tack additional charges on the DSL bill.
Fatal_ExceptionSystems EngineerCommented:
Call your ISP and just ask them how you are supposed to authenticate to their connection.  If PPPoE, then that is what you must use on your router.  And ask them specifically what username and password you should use.  You don't need to tell them it is a router.

The reason they have to tell you this, is that even if you were only setting up ONE system using PPPoE, without a router, then you would still have to insert that information into the connection properties on your computer.  The only difference is that it is your router making the connection instead.

FE
Bernie SalvaggioIT ManagerCommented:
Fatal's right about the PPPoE connection, if you got a username and password for your connection (not your primary email account) you'll have to enter that.  However... If you set it back to how it was before and go to the status page and your router has IP info, then you're connecting fine as far as the router and Earthlink is concerned.  Was the problem ever getting out to the Internet or getting DHCP info from the router? At any give point in time, regardless of PPPoE or whatever, if a computer is connected to your router you should be able to get DHCP IP info and connect to the router itself (via web browser).  If I read your problem right, this is where you're having problems, correct?

I had a problem very similar to yours a few years back.  I swapped out the Linksys router and it worked fine for a while, then I started having the same issue.  Resetting the power on the router cured it for a little while, then it'd happen again..  At the time, I read in some forums that Linksys routers were very succeptible to power issues.  So I replaced the router router again and bought one of thouse $35 UPS's from Office Max and plugged the router into that. I've had the same Linksys router now for 2 1/2 years and it's been working flawlessly ever since.

-Bernie
Admiral_SovereignAuthor Commented:
The PCs seem to have the problem the most when the laptop is connected...it appears to be the computers refusing to renew IPs, resulting in "Cannot Find Server" or "Internet Explorer could not open the search page" errors.
Bernie SalvaggioIT ManagerCommented:
When you get those errors, can you type in the IP for the router and bring up its config?
Admiral_SovereignAuthor Commented:
No I get the "Cannot Find Server" page.
Fatal_ExceptionSystems EngineerCommented:
Well, if you cannot ping the default gateway, then there is certainly something else going on here.  Have you scanned your systems for virii?

here are the correct Ping TS steps (from my site):

http://65.24.134.81/KipSolutions/P2PNetworks/PingUtility.htm

You might also want to rebuild your Winsock:

http://65.24.134.81/KipSolutions/WinsockFix/WinsockFix.htm
Admiral_SovereignAuthor Commented:
I will try your WinSock utility on the laptop when my father returns from CT.  He has Win2kPro.  Will this utility work on his OS?  In addition, he works for General Electric, who, frankly, is full of paranoid people.  He has BlackICE, Norton Corporate Edition and God-knows-what-else installed for security.  He has Ad-Aware and Spybot.  He also uses a VPN.
Fatal_ExceptionSystems EngineerCommented:
Yea, his laptop was probably configured by the GE Admins, and they most likely locked it down pretty hard...   Also running on a domain setup, so you may have trouble getting past their security..  you may not be able to run the utility, but it is good to go for W2K also...

FE
Doctor_OldsCommented:
The problem is that the ADSL Modem given to Earthlink ADSL customers is not a Router.  It only allows 1 (one) PC to access the Internet using 1 to 1 NAT. It is known as a UHP Modem.

Details here:
<a href="http://www.dslreports.com/faq/4954"><b>What is a UHP modem?</b></a>

To share the Earthlink ADSL connection will require a Router with multiple ports.  

There are basically two (2) setup solutions:

1] Earthlink offers (as in it's not a requirement) a Home Networking Package with networking support for $9.95 extra per month and a "free after rebate" Router, but you do not have to purchase it to share the connection.  You also do not have to pay the extra fee if you want to use your own Router.  The extra service is 100% optional.  It is actually a good deal for people that know nothing about Private LANs and how to set them up.

2] Purchase any Broadband Router you prefer, but remember that Earthlink will not help you set it up (so don't bother asking them, they will say no) or troubleshoot problems while it is attached to their UHP Modem.  That is fine if you know how to run and maintain your own private LAN (or are willing to learn on your own).  If you need your hand held in running a LAN, then the Home Networking package might benefit you, but it is not required.  If you know about Private LANs then get busy setting it up and enjoy it as I've have since my Earthlink ADSL was installed over 5 years ago.

To use any Router with the Earthlink UHP Modem will require you to decide how you want to set things up.  I recommend option #2 myself, but you do lose access to the diagnostics in the UHP modem when it is in Bridge Mode.

1] The UHP Modem setup in UHP Mode (aka PPPoE Mode) and the Router in DHCP Mode so that Double NAT is being performed.  All PCs connected to the Router will now have access to the Internet.

<a href="http://support.earthlink.net/mu/1/psc/img/walkthroughs/hardware/UHP/6898.psc.html">How to Configure the Unified Hardware Platform (UHP) DSL Modem</a>

2] The UHP Modem setup in Bridge Mode and the Router in PPPoE Mode to connect to Earthlink's network.

<a href="http://support.earthlink.net/mu/1/psc/img/walkthroughs/hardware/UHP/7222.psc.html">How to Change UHP Modem from PPPoE Mode to Bridged Mode</a>

Hope this helps and that it clears up the original poster's confusion..

Regards,

Doctor Olds

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Admiral_SovereignAuthor Commented:
OK, but WinPoet will not load.  I get the following: Failed to create WinPoet v4.0 Connection phone book entry."
ravipandeyCommented:
well.......... talking about getting connected
assign all your computers static IP`s in the range of the router`s....
who is your isp?
what`s the modem`s model? (some modem`s have built in DHCP)
Admiral_SovereignAuthor Commented:
I tried Static, failed.  ISP is EarthLink..  Modem is a Cayman 3300 Series.  One Ethernet port.
Fatal_ExceptionSystems EngineerCommented:
I just finished setting up an Earthlink DSL connection, Speedstream Modem 5100, with a router setup.  Had to call their tech support line, but they were very explicit and helpful.  On the Speedstream there is an option for Bridge mode, where you push the PPPoE connection to the router.

Suggest you call Earthlink and have them walk you through it.  They don't mind a bit helping you with your own router, at least my tech support guy did not...

FE
Doctor_OldsCommented:
If you want to use a Router then you don't use WinPoet which is for only one PC to have access.  Plus WinPoet isn't needed on XP as XP comes with it's own PPPoE software, but you don't want that either.  Remove WinPoet.

a] You set all PCs to "Obtain IP Address Automatically".

See image:
http://www.dslreports.com/r0/download/593072~cc158c2ceecddec8e23197b7b76a0f90/3SetupXP_PC.gif

b] With one PC hooked directly to the Netopia UHP Modem, you will need to put it into Bridge Mode.  It's IP is http://172.16.0.254/

++++++++++++++++++++++++++
How do I put the Netopia 3341 UHP Modem from EL into Bridge Mode?
http://www.dslreports.com/faq/9798
++++++++++++++++++++++++++

c] Then you add your Router between the Netopia and one PC so you can setup your Router to handle the PPPoE. Release and renew [Click Start, Run Type "cmd" (minus the quotes) press enter to open a Command box, now type "ipconfig /release" wait 30 seconds, type "ipconfig /renew" (minus the quotes)] your IP so it goes from http://172.16.0.254/ to the IP of  http://192.168.x.x that is your Router's IP address.

Only enter your full username and password into the Router for a PPPoE connection.  Choose "Always On" as the connection type if that is a Router connection type option.

d] All other optional Router fields should stay blank (i.e., Domain Name, Host Name, Service Name - leave empty).

e] Now configure all the PCs to never dial a connection, but to use the existing LAN connection only.

See Image:
http://www.dslreports.com/r0/download/593071~6d76f25c3ea1fe5fff35e3fe23d655eb/2Setup_LAN.gif

Enjoy your LAN as it should be working now.

Finally tweak each PC for Broadband.

++++++++++++++++++++++++++
How can I tweak my connection for better speed and performance?
http://www.dslreports.com/faq/2224
++++++++++++++++++++++++++

Regards,

Doctor Olds
Doctor_OldsCommented:
>> I just finished setting up an Earthlink DSL connection,
>> Speedstream Modem 5100

There is a Firmware update that you should check into for the Earthlink 5100 UHP Modem to make sure it has the latest fixes....

http://www.dslreports.com/faq/10134

Regards,

Doctor Olds
Fatal_ExceptionSystems EngineerCommented:
Thanks, Doc!
Admiral_SovereignAuthor Commented:
What about Win2kPro?  What should I do with PPPoE here?
Doctor_OldsCommented:
>> What about Win2kPro?  What should I do with PPPoE here?

The whole point of a Router is to have it handle the PPPoE connection for the entire LAN and you should now remove/un-install all PPPoE software from ALL PCs you may have installed it on. It is no longer needed and it may interfere with your Networking if left installed.

The PCs get their Private IPs from the Router (set all PCs to DHCP aka "Obtain IP Address Automatically") and the Router using PPPoE gets it's Public IP from the ISP's Radius server.

Regards,

Doctor Olds
Fatal_ExceptionSystems EngineerCommented:
Yep..  just use plain old ethernet to handle your internal LAN...
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