Problem With Internet...

[Brett Farrenkopf]

Okay I have a network going between two computers, one upstairs and one downstairs. Tey are connected by a router and the cable modem is downstairs. For some reason I can't seem to get the internet to work on the upstairs computer. Everything else works though, for example I can move files and etc. I just can't seem to get the internet to work. If you guys have any possible solutions please help. My e-mail is kevingrt13@hotmail.com and my AIM is UmdTerps13

[Misa]

I think I need a little more information about your network topology. The cable modem is obviously connected to your ISP/the Internet. Where's the cable modem plugged in? Is whatever's providing routing between your machines and the Internet doing NAT? How are you handling your inside addressing?

[Brett Farrenkopf]

The cable modem is connected to my PC downstairs, I don't know what you are talking about with NAT, and Inside Addressing what do you mean?

[Misa]

Okay, so the cable modem is connected to the downstairs PC. I'm going to assume then that your downstairs PC has a second network card and that's where it plugs into the router.

Now: does the downstairs PC get its IP address through DHCP ("Obtain an IP address automatically") or have you specified one?

Same question for the upstairs PC: does it get one through DHCP or did you type one into the Control Panel/Network box?

[Brett Farrenkopf]

Downsatirs-Automatic

Upstairs- Manuel I think

[sven verhaegen]

this might be a simple question but a pretty important one , this computer that links to the internet does it have gateway functionality activated ??

....in the same way a router works for the up to downstairs comunication the device which connects to the internet should function as a gateway to the internet , probably your local PC not connected to the modem sends it packets by default to the other PC trough the default gateway which is the router but that router has no gateway to the internet set, moreover a PC standardly does not work like a router forwarding packets between multiple virtual or physical interfaces it posesses and this function needs activation.... , you should thus not only look for the routing from the problem PC to the working PC but also form the router to the internet and even the gateway functionality of the PC connected directly to the internet

hope this helps ....

[Steven Sim Kok Leong]

Hi,

I am using a cable modem and SMC barricade router at home.

The SMC barricade router (as with most cable modem / adsl routers) double up as the DHCP and NAT server. It also works as a printer server and performs port forwarding for you to setup servers on your network for Internet access.

As long as you set your systems in automatic DHCP mode (I use both linux and windows), your broadband router will allocate both the DHCP IP address and the default gateway information to your system.

Some troubleshooting:

1) Check the link light on your router switch port. If it is on, your physical cabling is working end-to-end.

2) Check that you have enabled DHCP on your system.

3) Check the allocated IP address:

On Windows, # ipconfig -a
On Linux, # ifconfig -a

You should normally get an IP address in the 192.168.0.0 range.

3) Check your netstat table for your default gateway:

# netstat -rn

Hope this helps. Regards.

Steven Sim Kok Leong

[Steven Sim Kok Leong]

Hi,

Typo:

3) Check the allocated IP address:

On Windows, # ipconfig -a

Should be:

On Windows, # ipconfig /all

Hope this helps. Regards.

Steven Sim Kok Leong

[Steven Sim Kok Leong]

Hi,

>> Downsatirs-Automatic
>> Upstairs- Manuel I think

You are using manual for your upstairs PC, that's the problem.

Please set it to automatic, otherwise the router can't assign you the DHCP IP address and the default gateway information.

Hope this helps. Regards.

Steven Sim Kok Leong

[Brett Farrenkopf]

Okay...

Steve I put it on automatic and it still does not work...

Sven, I see what you mean but what can I do about it?

And if any of you have an e-mail or AIM that'd be great my e-mail is kevingrt13@hotmail.com

My AIM is UmdTerps13

[Misa]

Okay, so we have the cable modem connected to the downstairs PC, which is then connected to the router, which has the upstairs PC plugged in.

I think this is more complicated than you think it is. Your basic problem seems to be one of network addressing and routing.

My best suggestion is that you take a third PC and plug the cable modem into it. Turn this PC into a firewall. That means turning on routing and if done correctly, it will also help to protect you from some Internet nastiness. (I just saw a good book on this; will try to find the title.) On the second NIC of this new PC, choose a new address scheme -- say, 172.16.250 network. So the second NIC of your new PC, the primary NIC of the downstairs PC, and the primary NIC of the upstairs PC will all be 172.16.250 network.

Basically, the thing into which the cable modem is plugged must be able to receive its network information via DHCP (this is what MSoft means by "automatically"). You have to have the "automatic" network on the Internet side of a host, and a "private" network (with different numbers) on the other side. There are specified ranges of addresses that you are supposed to use for "private" networks. Problem is, your ISP may also be using some of them, in which case you have to avoid doing so.

If this sounds overwhelming (and it's a lot for someone who just wants to set up a second PC for the Internet), maybe your ISP can give you a pointer. I think that most/all of them say they won't help you with this type of thing, but maybe they CAN refer you to a local person whom you can pay to help set it up.

--Misa

[Misa]

By the way, I'm going on the assumption that your ISP will allow you only one DHCP address. That seems to be fairly typical. That's one probable reason you can't get automatic/DHCP to work with the second PC (routing issues aside).

--Misa

[Brett Farrenkopf]

I don't think it's that complicated though because there is a technian that used to come to my house but can't anymore that fixed it once in a sinch.

[Brett Farrenkopf]

Might this be a problem... On the upstairs or client computer it says Ip Routing isn't Enabled, how do I change that

[Misa]

Off the top of my head,I would say that no, that shouldn't be the problem. The downstairs one (connected to the cable modem) is the one that needs to do routing. (But doing it this way is not an optimal configuration.)

[Bill Nichols]

Brett, PMFJI, but I'm thinking possibly the best solution for you (if doable) would be to reconfigure your physical setup so the router comes after the modem but before the PCs. How many ports does the router support? If only one, then this won't be of any help; however, if you have one with more than one port you should be able to feed both PCs off the router, which would solve the problem.

Good luck!

Bill

[Patrick Ruane]

If i'm understanding this thread right, you've got the cable modem / router directly connected (usb or ethernet) to the downstairs pc. This is then networked (separate network card) to your upstairs pc. Your downstairs pc can connect to the internet and the upstairs pc can talk to the downstairs pc but not to the internet, right? (If i'm wrong then the rest won't make any difference). Have you set up Internet Connection Sharing on your downstairs pc? (as this is a microsoft forum, i'm guessing you're using windows).

Basically, the upstairs pc needs to have a static IP address, as does the internal network card on the downstairs pc and the upstairs pc needs to have it's gateway set as the downstairs pc (along with the correct DNS servers as given by your isp if you want to get onto the web - you can find out using ipconfig on the downstairs pc). Then, go into Control Panel > Add & Remove Programs > Windows Setup > Internet Tools(?) and enable Internet Connection Sharing.

Follow the wizard, entering the correct internal and external adapters and bob's your mother's father.

If i'm way off on this one, please don't flame me everyone, but that's my two pennies worth.

[Patrick Ruane]

ps

It's rare to find an isp that will let you plug both pc's into the router / modem. They don't like that kind of thing and will generally specify the MAC address of one pc to stop you from trying (their excuse is that it's more secure, but they're really trying to save bandwidth).

[Brett Farrenkopf]

Okay Patrick, I thinkk you are right, but can you lead me through how to do this or anyone can lead me through this?

[Patrick Ruane]

It's hard to explain the above in simpler terms. Set up your network as it was so the downstairs pc can connect to the internet and the pc's can communicate then:

1. Click Start > Settings > Control Panel and double click Add & Remove Programs
2. Click on the Windows Setup tab
3. Click on Internet Tools(?) and tick the box next to Internet Connection Settings
4. Follow the wizard, sharing the correct interfaces
5. Set the gateway on your upstairs pc to the internal IP address of your downstairs pc.
6. Run IPCONFIG from a command prompt on your downstairs pc, make a note of the DNS servers and enter these addresses into the upstairs pc.

If you search the microsoft website or yahoo for Internet Connection Sharing you might get a better description.

HTH

Patrick

[Jon Finley]

Otherwise.... you're looking at setting up IP forwarding on the downstairs system, so the 2 cards can talk.


Jon

[Misa]

Someone suggested to me that there is a Linksys product, P/N BEFSR41, that might help out. It's supposedly an appliance that does "firewall" and is a 4-port router. Supposedly this will DHCP your ISP, handle NAT, and everything. $50-$75USD.

[Bill Nichols]

Absolutely right, Misa. It's a 4-port router, & serves as a physical firewall with NAT, plus DHCP to handle both PC's dynamically, & all the ISP sees is one IP, the one into the router. It's very simple to set up & works like a real champ! Another nice thing about it is that if the ISP periodically re-leases IP addresses to the modem, the router recognizes that automatically too. It's also smart enough to be able to tell whether the NICs are 10BaseT or 10/100, a definite advantage if you're dealing with an older machine that has a working NIC, just not the latest/greatest.

The one caveat is that if the boxes have been connected with ICS, you can't reutilize the current Cat5 cable between them, since ICS uses crossover cable & the cabling from router to PC has to be straight Cat5 patch.

Bill

[Brett Farrenkopf]

If i have DHCP downstairs and Manuel upstairs, do I need both DHCp or both Manuel. And how do you do it manuel downstairs?