Network help.

[juneau]

Bit of background....

Built new main PC a few months ago and it uses the Abit IP35 Pro motherboard, which has two ethernet ports.

Built a Media PC out of spare parts a little over a month ago, and rebuilt it again a week ago with new parts as the old parts weren't fast enough. New C2D setup on a Gigabyte P31-DS3L.

Now, i need to transfer files between the two PC;s every now and then and i got sick and tired of burning off 4x DVDRW discs so opted to make use of the second ethernet port on my main PC and buy a X-Over cable.

Now considering i hadn't used anything i learned about networks since i left college. My knowledge is even way beyond rusty so i followed a guide.

http://www.hardwaresecrets.com/article/426/1

The first 4 pages don't really apply to me as i don't want my Media PC to share my main PC's internet connection. So i started from the bottom paragraph of page 4.

If you do not have broadband Internet access – i.e. you have just one network card installed on each computer – the procedure is different, as you won’t be able to share your Internet connection as you don’t have one. In this case the easiest way (in our opinion) to setup your network is by configuring it manually. This is done at the TCP/IP configuration settings of each computer, and we will show you how this is done on the next page.

On the next page i read and followed this,

If you do not have broadband Internet access – i.e. you have just one network card installed on each computer – you will need to manually configure the TCP/IP protocol. You should follow all the steps present on this page but when comes to configuring the TCP/IP protocol (Figure 9) you need to configure it manually instead of automatically.

At one of the computers, you should, on the screen present on Figure 9, configure your computer like this:

* Select Use the following IP address
* IP address: 192.168.0.1
* Subnet mask: 255.255.255.0
* Default gateway: 192.168.0.1
* Select Use The Following DNS server addresses
* Preferred DNS server: 192.168.0.1

You should configure the other computer like this:

* Select Use the following IP address
* IP address: 192.168.0.2
* Subnet mask: 255.255.255.0
* Default gateway: 192.168.0.1
* Select Use The Following DNS server addresses
* Preferred DNS server: 192.168.0.1

All done.

Now to setup file sharing between the PC's. After i slight idiot moment and messaging Darth for help i just went to the My Network Places folder and hit F5 to refresh the drives available.

All done! Quick check to test the connection is working fine. All working fine.

But here's the problem. When the connection between my 2 PC's is enabled, roughyl 10-15mins later i can no longer access anything on the internet on my main PC. It's showing as connected in the network connection tab. The ENet light on my modem is on, yet every page i visit throws back an instant error of 'Server not found'. Disable the connection to my Media PC on my main PC and my internet starts to work again.

Now i'm stumped. Any ideas for the networking noob?

[Hammy]

Do you have the drives mapped on each computer?

If they aren't mapped you wont find anything.

Windows Firewall?

Firewall at all?

[-IRC-MIKE]

Out of curiosity, Did you enable internet connection sharing on your main rig? If not you should enable that, reboot.

[mapes]

Because you have entered a default router on the second private network interface. Which means which ever interface gets enabled last ends up routing all packets. So in effect your trying to reach the internet through the second interface....Welcome to the wonderful world of MS routing.... So just

1. Go into the second interface tc/ip options and remove the default route.
2. Save
3. Disable both interfaces
4. Re-enable the second interface first
5. Re-enable the first interface

you should be good to go.

[juneau]

Out of curiosity, Did you enable internet connection sharing on your main rig? If not you should enable that, reboot.

But i don't want to share my internet connection with other PC's on my network. That's how i understand it.

Because you have entered a default router on the second private network interface. Which means which ever interface gets enabled last ends up routing all packets. So in effect your trying to reach the internet through the second interface....Welcome to the wonderful world of MS routing.... So just

1. Go into the second interface tc/ip options and remove the default route.
2. Save
3. Disable both interfaces
4. Re-enable the second interface first
5. Re-enable the first interface

you should be good to go.

Let me see if i can get my head around this. Because i'm setting up a network on the second ethernet port after i setup my internet on the first ethernet port, XP thinks to access the internet throught the second port and not the first and therefore it's looking for www.google.com on my home network?

1. You've lost me already. Default route?

[mapes]

Sorry number one should read

1. In the second interface tcp/ip options make this value blank

Default gateway: 192.168.0.1

go on to steps 2-5

[-IRC-MIKE]

I believe you need to turn on ICS in order to route traffic or else one door closes when the other opens. I could be wrong but I've never tried to do this without wanting both machines to have access to the internet. I do recall having trouble keeping the main pc connected without ICS enabled. I dunno.. we'll see. Both were fighting as client machines to be the master browser....

[Trooper110]

Just follow the steps Basically what he was saying is that MS is retarded and assumes that because you set up the second connection after the first that you want all traffic to go there,even though both are enabled.

By disabling both, and then re-enabling your local connection followed by the connection to the router, Windows now assumes taht you want that connection to be your default. It's stupid, but that's Windows and networking for you.

I've been able to connect to a local connection as well as the internet on a different interface without sharing the network Mike. Did it back in August when I was getting my cousin's laptops ready for college.

[juneau]

Just follow the steps Basically what he was saying is that MS is retarded and assumes that because you set up the second connection after the first that you want all traffic to go there,even though both are enabled.

By disabling both, and then re-enabling your local connection followed by the connection to the router, Windows now assumes taht you want that connection to be your default. It's stupid, but that's Windows and networking for you.

I've been able to connect to a local connection as well as the internet on a different interface without sharing the network Mike. Did it back in August when I was getting my cousin's laptops ready for college.

Going to go through it later, the little lady is on her way and she huffs and puffs when i mess around on my PC for too long while she's here PS, i dont have a router. Guess this doesn't matter though.

Just noticed something. Not sure if this makes a difference.

The two ports on my main PC. LAC1 is in use with my home network. LAC2 is in use with my modem.

[mapes]

hmmm how to explain this..... Ok networks operate at many different levels. What we are looking at here are level 2 and 3. Layer 2 is known as Ethernet. Layer 3 is known as IP.

Layer 2's job is to send packets to hosts on the same network. It uses a hardware address called a MAC address which is set by the network card vendor. When your machine boots up it sends out whats called an ARP packet. Other machines on the network record that ARP packet in a table (in windows type arp -a to see it). When machines need to send packets to other machines on the same net they use Ethernet and send packets directly to each other by addressing packets with the recipients MAC address.

This is all well and good but how do you talk to other machines on other networks....Thats layer 3 ... specifically IP. When you want to talk to a host on a different network your machine has no idea the path to the remote network instead it has whats called a default route (or Gateway in windows parlance). What that says if I need to send a packet to another host on another network and I don't know how to send it I just send to my default gateway and let it deal with it.

Think of mailing a letter...Ok this is a bad analogy but, it'll work. Ethernet is you and your car. If you want to drop a letter off somewhere where you know how to drive to. You just get in your car ...drive to the address and drop off a letter. IP is if you want to mail a letter to Russia which you don't really know how to drive there....you drive to the default gateway/router which in this bad analogy is the Post Office. Drop the letter off at the PO and let them deal with routing it. That in essence is IP routing explained...

So in effect when you have your your first interface up and it's default route is set (type netstat -nr in windows....the last route is the default gateway) all packets are correctly routed to your internet gateway.....when you bring up the second interface because it too has a default gateway set ...it overwrites the first one because it's like highlander....."There can be only ONE" default route/gateway.... And all traffic then goes out the second interface. Well not all traffic but traffic destined for other networks (i.e anything on the internet)


Hope this helps

[mapes]

I believe you need to turn on ICS in order to route traffic or else one door closes when the other opens. I could be wrong but I've never tried to do this without wanting both machines to have access to the internet. I do recall having trouble keeping the main pc connected without ICS enabled. I dunno.. we'll see. Both were fighting as client machines to be the master browser....

He's not routing between nets.... he wants

First interface to go to internet....default should go here

Second interface to go private network between two machines just for SMB or windows filesharing between the two machines No default gateway setting here...


And yes MS is retarded for putting the Default Route as a interface property. When it's more of a global setting.

[juneau]

Quick question before i disappear for a couple of hours. Do i remove the default gateway on my Main PC only? Or both of my PC's?

If so... Quick rundown

Main PC

* IP address: 192.168.0.1
* Subnet mask: 255.255.255.0
* Preferred DNS server: 192.168.0.1

Media PC

* IP address: 192.168.0.2
* Subnet mask: 255.255.255.0
* Preferred DNS server: 192.168.0.1

Disable Home network and Internet connection on Main PC
Disable Home network on Media PC
Enable Home Network connection on both PC's
Enable Internet connection on Main PC

[mapes]

Quick question before i disappear for a couple of hours. Do i remove the default gateway on my Main PC only? Or both of my PC's?

If so... Quick rundown

Main PC

* IP address: 192.168.0.1
* Subnet mask: 255.255.255.0
* Preferred DNS server: 192.168.0.1

Media PC

* IP address: 192.168.0.2
* Subnet mask: 255.255.255.0
* Preferred DNS server: 192.168.0.1

Disable Home network and Internet connection on Main PC
Disable Home network on Media PC
Enable Home Network connection on both PC's
Enable Internet connection on Main PC

Does your HTPC have two interfaces setup? If yes then yes remove the default gateway from the second interface. Also remove the Preferred DNS server: 192.168.0.1 from both machines second interface. Since it does you nothing and might complicate the issue.

So to sum up

The first interface for both machines should not be changed.

The second interface for both machines should ONLY have ....1)an IP address and 2) a subnet mask.

If you do that then disable both interfaces and then bring them both up (won't matter on the order then)....Everything should be fine.

[juneau]

Main PC has 2 interfaces. Media PC has 1. Thanks for all the help so far Mapes.

[mapes]

Does the media PC connect to the internet?