2 pcs w/router & dsl, 1 pc won't connect to web

Hello:

Hopefully this is the right forum to post this question.

I have a home PC which connects to the web via an ActionTec DSL modem. I recently purchased a Belkin 4-port router so I could use my work laptop at home. Both pcs use WinXP Pro OS.

After setting up the router, both pcs connected to the web just fine. However, it took only a few days before the home pc stopped connecting. I tried the following:

different (new) router
new network cables
resetting router
resetting dsl modem
going back to original setup (removed router and laptop from equation)

No luck. My home pc would not connect to the web.This is strange because I thought the original NIC must be defective and so had the motherboard replaced under warranty (NIC is integrated on MB). It did not work.

Then I installed a standalone NIC and, strangely, the pc now connects.

I find this behavior very odd and am baffled as to what is going on.

I appreciate any suggestions as to what the problem might be.

Cheers, Rose

 

Old nic could have gone bad, or maybe you did a system restore and it changed the TCP/IP settings for the nic from obtain automatically to what it was before you set things up.

 

What model ActionTec DSL modem?

 

It is an ActionTec DSL model w/wireless gateway model GT701-WG.

 

I don't think the old nic was bad but in any event had the system board replaced under warranty (nic is integrated on board).

I did not do any system restore. TCP/IP settings for both the home pc and work laptop have always been (and still are) set to dhcp.

 

Well this is the way I see the problem.
You have 2 routers setup.
The ActionTec and the Belkin.

Basically you have 2 devices handeling routing and DHCP.

Simple solution.

Go into the configuration of the Belkin and turn off DHCP.
DO not plug the ActionTec into the WAN or Internet port of the belkin but rather one of the LAN ports.

What was happening was your PC was receiving it's network address from the wrong device.
Configuring in the above method should work much better and allow your internet applications to work correctly.


Look in your user manual and you will see your device includes NAT and DHCP.

 

Thanks for the info. I tried your suggestion and it worked. Except, now my work laptop will not connect! I'm very confused! Please let me know if you have any other ideas. Your help is much appreciated. Cheers, Rose

 

From a command prompt on both machines run ipconfig /all > c:\config.txt


Copy and paste the contents of both text documents here for us to see.

The text will be located at the root of C:\

 

Scott -- here's the info you requested. Thanks, Rose

Home PC config.txt:

Windows IP Configuration

Host Name . . . . . . . . . . . . : SEWARD

Primary Dns Suffix . . . . . . . :

Node Type . . . . . . . . . . . . : Hybrid

IP Routing Enabled. . . . . . . . : No

WINS Proxy Enabled. . . . . . . . : No

DNS Suffix Search List. . . . . . : domain.actdsltmp

Ethernet adapter {2FA7D30E-9831-475F-9323-4BB2C9BB7C7B}:

Connection-specific DNS Suffix . :

Description . . . . . . . . . . . : Nortel IPSECSHM Adapter - Packet Scheduler Miniport

Physical Address. . . . . . . . . : 44-45-53-54-42-00

Dhcp Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : No

IP Address. . . . . . . . . . . . : 0.0.0.0

Subnet Mask . . . . . . . . . . . : 0.0.0.0

Default Gateway . . . . . . . . . :

DHCP Server . . . . . . . . . . . : 255.255.255.255

Ethernet adapter Local Area Connection 4:

Connection-specific DNS Suffix . : domain.actdsltmp

Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet for hp

Physical Address. . . . . . . . . : 00-11-85-8D-F8-89

Dhcp Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : Yes

IP Address. . . . . . . . . . . . : 192.168.0.100

Subnet Mask . . . . . . . . . . . : 255.255.255.0

Default Gateway . . . . . . . . . : 192.168.0.1

DHCP Server . . . . . . . . . . . : 192.168.0.1

DNS Servers . . . . . . . . . . . : 192.168.0.1

216.17.128.1

Lease Obtained. . . . . . . . . . : Sunday, September 25, 2005 4:37:06 AM

Lease Expires . . . . . . . . . . : Monday, September 26, 2005 4:37:06 AM


LAPTOP

Windows IP Configuration

Host Name . . . . . . . . . . . . : fcrs0439l

Primary Dns Suffix . . . . . . . : americas.hpqcorp.net

Node Type . . . . . . . . . . . . : Hybrid

IP Routing Enabled. . . . . . . . : No

WINS Proxy Enabled. . . . . . . . : No

DNS Suffix Search List. . . . . . : AMERICAS.cpqcorp.net

AMERICAS.hpqcorp.net

hpqcorp.net

cpqcorp.net

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . : domain.actdsltmp

Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet

Physical Address. . . . . . . . . : 00-0D-9D-92-04-84

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

216.17.128.1

Lease Obtained. . . . . . . . . . : Sunday, September 25, 2005 5:58:12 AM

Lease Expires . . . . . . . . . . : Monday, September 26, 2005 5:58:12 AM

Ethernet adapter Wireless Network Connection:

Media State . . . . . . . . . . . : Media disconnected

Description . . . . . . . . . . . : HP WLAN 802.11a/b/g W500

Physical Address. . . . . . . . . : 00-11-85-1B-94-C6

 

Ok something fishy is going on here.

Notice your desktop received an IP address of 192.168.0.100 and your laptop received an address of 192.168.0.2
Both are on the same subnet but are getting their address from 2 diffrent DHCP servers.

Lets break this down to the simple level and work by process of ellimination.

First it looks like your mother board NIC may be working but has no cable plugged into it.

Lets take the gateway out of the loop for now.
Plug your destop motherboard NIC directly into the DSL modem, restart the computer and give me another ipconfig /all > c:\motherboard_NIC.txt
and post here so we can see what the DSL modem gives us.

 

Scott: Here's the motherboard_NIC.txt:

Windows IP Configuration

Host Name . . . . . . . . . . . . : SEWARD

Primary Dns Suffix . . . . . . . :

Node Type . . . . . . . . . . . . : Hybrid

IP Routing Enabled. . . . . . . . : No

WINS Proxy Enabled. . . . . . . . : No

DNS Suffix Search List. . . . . . : domain.actdsltmp

Ethernet adapter Local Area Connection 4:

Connection-specific DNS Suffix . : domain.actdsltmp

Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet for hp

Physical Address. . . . . . . . . : 00-11-85-8D-F8-89

Dhcp Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : Yes

IP Address. . . . . . . . . . . . : 192.168.0.100

Subnet Mask . . . . . . . . . . . : 255.255.255.0

Default Gateway . . . . . . . . . : 192.168.0.1

DHCP Server . . . . . . . . . . . : 192.168.0.1

DNS Servers . . . . . . . . . . . : 192.168.0.1

216.17.128.1

Lease Obtained. . . . . . . . . . : Sunday, September 25, 2005 8:36:15 AM

Lease Expires . . . . . . . . . . : Monday, September 26, 2005 8:36:15 AM


Ethernet adapter {2FA7D30E-9831-475F-9323-4BB2C9BB7C7B}:

Connection-specific DNS Suffix . :

Description . . . . . . . . . . . : Nortel IPSECSHM Adapter - Packet Scheduler Miniport

Physical Address. . . . . . . . . : 44-45-53-54-42-00

Dhcp Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : No

IP Address. . . . . . . . . . . . : 0.0.0.0

Subnet Mask . . . . . . . . . . . : 0.0.0.0

Default Gateway . . . . . . . . . :

DHCP Server . . . . . . . . . . . : 255.255.255.255

I'm probably grasping at straws here, but does it make any difference that my work laptop is part of a domain (I log into my work network via VPN)? Before I got the laptop, I used my home pc to log into work via VPN (Nortel Contivity VPN Client).

Thanks, Rose

 

Ok looks good.

Will the desktop surf in that configuration?
If so remove that added NIC and lets move on.

Connect directly to the modem with the laptop and do a ipconfig /all > c:\laptop.txt
Will the Laptop surf in this configuration?

Sorry Im only doing one step at a time but I dont want to get off track.

 

Yes I can surf from the desktop.

Here's the info for the laptop -- it is connected directly to the modem:

LAPTOP Config

Windows IP Configuration



Host Name . . . . . . . . . . . . : fcrs0439l

Primary Dns Suffix . . . . . . . : americas.hpqcorp.net

Node Type . . . . . . . . . . . . : Hybrid

IP Routing Enabled. . . . . . . . : No

WINS Proxy Enabled. . . . . . . . : No

DNS Suffix Search List. . . . . . : AMERICAS.cpqcorp.net

AMERICAS.hpqcorp.net

hpqcorp.net

cpqcorp.net



Ethernet adapter Local Area Connection:



Connection-specific DNS Suffix . : domain.actdsltmp

Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet

Physical Address. . . . . . . . . : 00-0D-9D-92-04-84

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

216.17.128.1

Lease Obtained. . . . . . . . . . : Sunday, September 25, 2005 5:58:12 AM

Lease Expires . . . . . . . . . . : Monday, September 26, 2005 5:58:12 AM



Ethernet adapter Wireless Network Connection:



Media State . . . . . . . . . . . : Media disconnected

Description . . . . . . . . . . . : HP WLAN 802.11a/b/g W500

Physical Address. . . . . . . . . : 00-11-85-1B-94-C6

 

Something strange is going on.

The Desktop received an IP address of 192.168.0.100
The manual for the DSL Modem/Router shows the default DHCP scope starts with 192.168.0.2 and goes to 192.168.0.254

Why the Desktop is getting served .100 is beyond me unless the Belkin handed it out.

Heres what I would do:
The Action Tec will do everything you need to do on your network.
Get a decent quality hub so that you have multiple ports and loose the Belkin. You dont need it take it back or sell it.

Plug the Action Tec into the hub and connect your PC to the hub.
Since the Action Tec has wireless you can run the laptop over wireless if you like.
The web interface for the Action tec is at 192.168.0.1 and you can turn on wireless from there.

 

Thanks for all your help Scott. I'll get a hub and hopefully the problem will be solved. Cheers, Rose

 

I believe it is possible with DHCP for the BELKIN ROUTER to have been earlier the DHCP Server (192.168.0.1) which initially gave the IP 192.168.0.100...

Later you connected Desktop directly to the Modem (also 192.168.0.1) and Desktop just renewed the same IP Address with a different DHCP Server with the same IP Address. It's actually not super surprising because if the other parameters in the DHCP Request were all ok, and that IP 100 was valid in the Modems DHCP Pool Range, for it to allow Desktop to have it.

By renew I mean technically it did:

DHCP Request (including asking for that specific IP Address)

And the Modem (as a DHCP Server) did:

DHCP Ack (acknowledge) (or in other words, "that sounds good to me... ")

(There could have been a little bit more to the DHCP transaction than that, but that's basically the gist of it.)

* It's also possible no DHCP transaction got done at all. The refresh period perhaps hadn't expired nor the DHCP Lease. So Desktop just continued using the same IP Address ... for a period of time. Did you try that with a "ipconfig /release" and an "ipconfig /renew" ?

...........................................................................................

In between there was probably also an ARP who has 192.168.0.1, since Desktop could no longer find that IP on the old Ethernet MAC Address.

If Desktop had failed to find DHCP Server on 192.168.0.1 it would have reverted to:

DHCP Discover (by Ethernet Broadcast) looking for a new DHCP Server.

( * I hope I'm not rusty on DHCP. I used to manage 2 servers for some 20,000 cable modem subscribers. Too bad I gave someoone my book
Ted Lemon and Ralph Droms' "DHCP Handbook "!)

http://www.isc.org/index.pl?/sw/dhcp/

... I also have networks on yachts that have multiple connections possible to Internet. They have to switch between, for example Satellite and WiFi Hotspots, or Verizon Broadband. So I frequently have to deal with TWO DHCP SERVERS situations.

P.S. If this gets any more confusing you might want to have them grab WinPCAP and Ethereal and do some Packet Capturing. Ethereal is very good at telling you what's really going on.

Oh, also, get a "Switch" as in a Fast Ethernet 10/100 Switch. Noone buys a hub anymore these days. I doubt you'll even find one new in consumer electronics stores.

 

You are very correct! That was a slip of the tounge on my part.

 

Thank you for the info. I might try the ipconfig release & renew just to see if that works. In the meantime, I did purchase a switch which works -- both pcs now connect to the web just fine.

Cheers, Rose

 

No problem. Using two boxes that function as a NAT/ROUTER causes a double NAT (see the article at the top of the forums on Nat, Router, Firewalls.)

[Internet] <----> [NAT/Modem] <----> [NAT/Router] <----> [PC]

Where NAT = [Internet] <----> [NAT] <----> [Local Area Network]

Also two DHCP Servers on a network often causes problems. If you ever have to switch between two DHCP Servers having been on to just one always release and renew or reboot all computers on the network. Also it is a good idea in a transition to, believe it or not, have both DHCP Servers on for a few minutes ... turn on the 2nd one and then turn off the 1st one. This avoids you losing your IP Address altogether. (Although you could recover by temporarily putting a manual IP Address similar to the automatic settings. Make a note of what you've got, and keep in mind the range is 253 valid IP Addresses from .2 to .254. Your Subnet Mask is always 255.255.255.0. Your default gateway seems to always be 192.168.0.1. Make a note of those DNS Servers as well.) The "Network" itself uses address .0 and a sort of "All Stations" Broadcast reserves the address ending in .255 as well.

Another note, if you use a VPN to an office sometimes the VPN Server will have a security policy that will prevent access to your local LAN. If they do that this can break your Internet connection altogether especially if you go over LAN/NAT. This kind of thing involves talking to the Network Administrator(s) handling the VPN and hoping they will allow the LAN activity.