Internet Network...

[Niloc]

I have two computers with Ubuntu and one still on Win XP. Would it be possible to run all three on one ADSL internet connection, something like an Internet cafe?

I guess I will need a 'hub' but is it simply a matter of plugging them all in and away they go??

TIA,

Colin

[autonomous_unit]

Do you have some sort of ADSL modem now? Or are you just planning for a new connection?

The best way is to have a router that sits between the ADSL connection and all of the computers. It will serve a private LAN, meaning that each computer is connected to the router's "LAN ports" via an ethernet cable and configured to have a normal LAN connection to the Internet. The router will take care of sharing the single ADSL connection and IP address with all of the computers, so they won't know anything about the ADSL connection.

There are two types of router like this: ones that have an ethernet "WAN port" and ones that have a built-in ADSL modem. The ones with an ethernet WAN port will require an ethernet-based ADSL modem to connect into this port (a USB ADSL modem will not work). In either case, you configure the router with your ADSL account information (PPPoE or PPPoA subscriber name and password) via the router's web configuration page. I use an ADSL router but the kind with an ethernet WAN port are more common. I haven't looked at product availability or prices since 2004 when I bought my router...

If you do have a USB ADSL modem, you can attempt to configure one of your computers to act as the connection-sharing host instead of buying a router. But, I'd recommend getting a router instead.

[Niloc]

You must be looking over my shoulder, I have an ethernet ADSL modem so I will have to configure the router, I assume the subscriber name and password wiil be those I used for the USB modem?

Hopefully the router will solve my laptop to desktop Linux/Linux network problems also...

Thanks,

Colin

[autonomous_unit]

So you've bought an ethernet-based ADSL modem now, but you originally had a USB ADSL modem? Or do you mean you bought a router with built-in ADSL modem now? What's the make and model of the device?

Yes, the normal process with ADSL is that the modem implements something called an ADSL bridge, and then a PPPoE (PPP over ethernet) or PPPoA (PPP over ATM) connection is established via this bridge to actually talk to the provider and exchange Internet traffic. This PPP session uses a username and password, and that would have been configured in the connection manager software used with a USB modem. If you tried to connect a standalone ethernet-based ADSL modem to a PC, you'd still have to run a connection manager on the PC that runs this PPP session. However, with an ADSL router, the router itself will run the PPP session with its built-in modem and your PC will just see it as an IP router via LAN.

You also need some low-level circuit options called "VPI" and "VCI". You may already have these from the USB modem configuration but I am not familiar with those... If you ask on the main IT forum here, telling who your provider is and where you are located, someone probably knows the correct settings. Or you can try to get through to a tech support person at your provider.

[Niloc]

Yes, that is correct, I started with an ADSL USB modem then bought an ethernet ADSL modem but it only has a single ethernet connection. I thought if I got a 'Hub' I could use the same modem but connect all three machines to it.

I have the user name and password from the USB modem but the ethernet modem has never asked for either, I just plugged it in and away it went! I can even unplug it from one computer and into the other while staying on the internet and never lose a byte so it works very well.

[autonomous_unit]

That's interesting... did you buy the modem from your ISP? (Maybe it came pre-configured.) Do you have to run any connection software on the PCs or do you just configure them to use DHCP and get internet service over a regular IP LAN?

Maybe your "modem" is actually a router, in which case an ethernet switch might be sufficient. But, if it is really not a router, then you need a router to provide the connection sharing. You could get one of the ones with just a WAN ethernet port and several LAN ports (and wireless if you like) and probably save a few baht, versus having to get one with built-in ADSL modem.

I think you should be able to get a router for a few thousand baht at Pantip or similar IT malls.

[Niloc]

I bought the modem off a dealer in Chiang Mai, he was actually using it when he sold it to me, 750 baht I think so he may have configured it when he first used it.

The modem has only one output on the back which is labeled simply 'Ethernet' and of course the power and 'phone plug in.

All I want is something I can plug into 'Ethernet' from which I can connect three cables to my computers, two Linux and one Win XP and get the internet on all three. I thought that is what the 'Hub' would do?

[autonomous_unit]

I cannot answer for certain without knowing the exact model of your modem and how your current computers are configured in the network software. Your modem may actually be a router, meaning it is capable of serving multiple computers at once because it has an internal PPPoE client and does network-address translation to hide the LAN behind it. But, if it's a router, you must be running with the dealer's ADSL subscription (or a previous owner's) as the username+password are configured into the PPPoE client!

However, a plain ADSL modem normally does not do these things, and it is the computer that runs the PPPoE client. In this case, you probably do not want to try to run multiple PPPoE sessions over the modem at once, as you would have to do if you bought a simple hub/switch. I'm still not 100% clear on whether you've removed the PPPoE client from your PCs or whether you might still be using it with this modem instead of the old USB modem.

What is the exact brand and model of this modem? How exactly is the network connection configured in your PC? If you look up your PC's IP address on the network card settings when it is using the ADSL modem, what are the first two or three numbers? Does it start 192.168. or does it start with some other number?

A router sold for home use will typically have a 4-port ethernet switch, as well as a separate WAN port and possibly a wireless antenna. You can definitely use one of these with your modem, by connecting the router's WAN port to your modem's "ethernet" port, and then connecting your PCs to the router's LAN ports. This is the safest purchase. You can even ignore the router functionality (just use the device's web page to turn off DHCP) and then use the built-in switch as a hub, while leaving the WAN port disconnected.

You might be able to find an ethernet hub/switch for a little less money, but I cannot guarantee that you would actually be able to operate multiple PCs on the modem's internet connection at once with just a hub.

[Niloc]

If I go into 'Network Settings', 'DNS' the DNS Server is 192.168.1.1 (this is on the desktop using Ubuntu 6.10). The connection is shown as 'Wired Connection' ,Address DHCP.

The modem connection is shown as 'not configured'.

The modem is a XAVI Technologies Corporation, Model Name X8821r+. It is a white box with lights on the top, PWR,WAN,PPP.LAN and ALM.

I hope this helps...

Thank you for your assistance,

Colin

[autonomous_unit]

OK, I did a search for this modem and found a PDF manual online via google. You might want to do the same and download a manual for future reference... It is in fact a router with a built in PPP client. This raises the question of whose PPP login you are using currently.

So, you could simply purchase an ethernet switch (no point in getting a hub these days), and connect its uplink port to the modem's ethernet port and then put all your PCs on the other switch ports, as you originally hoped.

You should find a device configuration page if you visit http://192.168.1.1

The default username/password is admin/admin according to the manual I found. If it has been changed, then you may have to try to get this information from the dealer or else take a chance and force a reset to factory defaults.

Beware, however, that you'll need to know the settings for your ISP to return the device to operational status. Besides your own subscriber login/password, you'll need to know the VCI/VPI parameters that your ISP uses. You'd be able to get these from the device if you know the password. If you want to do a reset, the manual says to press and hold the little reset button on the back near the ethernet port.

[Niloc]

It aint easy is it? I found the website, tried admin/admin but no go, it looks like it has been changed but do I really need to change anything? It works perfectly right now so it should go equally well with a switch, connect the three computers and it should all be OK?

There is no 'button' on the back, only a tiny hole so it probably needs a paper clip but as I don't have the ISP parameters and I can't get into it anyway, if it works with a switch I will be content with that!!

Thank you for your efforts, I will purchase a switch and see how it goes....

Colin

[autonomous_unit]

Yes, it will work until whatever ISP account it is actually using has a problem and gets terminated...

Me, I'm the paranoid and geeky type who would not quit until I'd reset the thing, set my own password, and found the right ISP settings to use my own subscription...