Really weird network problem... Please help!

SomeoneWithAPurpose · 2009-04-25 22:43:22

This is really starting to tick me off, so I hope you can help me. This isn't exactly Archlinux related, but the problem persists on the whole network regardless of OS being used.

Ok, so I got my new D-Link 5-port switch home a few days ago. I wanted to hook up my laptop so it could access the internet.

I'll try to illustrate how the layout of the network is made up in my home:

Internet -------> Router -------> Switch -----------> My dad's computer
|
-----------> My switch -------------> My main desktop
|
-------------> My laptop

As you see, we split the internet between our 3 computers, where 2 of them are mine, and 1 is my dad's. The problem is, that we can't run more than 2 computers online. DHCP just won't function.

If I have both of my computers online, my dad can't connect to the internet. If my dad has his computer online, I can't connect with 1 of my computers. So we are constantly only able to be 2 on the internet. I see no logical explaination for why this is happening, because the internet is split on the first switch, to my dad and me, then from my own switch, I split my connection between my 2 computers.

Please help me, this is really giving me an edge. I REALLY hope you can help

gazj · 2009-04-25 22:54:20

Check you have not got more than one dhcp server running

Xyne · 2009-04-25 23:05:35

There's probably a limited IP address pool (2). Check that the router is running a dhcp server and that you're not getting the assigned IP addresses directly from the ISP's server further upstream.

Your local IP address as reported by ifconfig should in one of the following ranges:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255

If it's something else, you're router is basically acting as a switch (no firewall, no dhcp, etc... your computers are basically sitting naked on the internet) and you'll need to set up nat and dhcp.

If that's not the case, configure the local network mask in the router's menu to assign more addresses.

It could be something else, but that's the first thing that comes to mind. You should be able to access the router's menu in your browser (e.g. http://192.168.0.1, http://192.168.1.1, http://127.0.0.1, etc... check the manual or google it if those don't work).

I hope this helps. I know how annoying network problems are. It's one of those things that "should just work".

SomeoneWithAPurpose · 2009-04-25 23:30:10

Atm, my Linux machine is offline because of this problem, so I will have to use my Windows machine:
ipconfig /all on Windows says...

Hostname: <My machine name>
Primary DNS-suffix: <blank>
Nodetype: Unknown
IP-routing activated: No.
WINS-Proxy activated: No.
Searchlist for DNS-suffix: opasia.dk

Connection-specific DNS-suffix: opasia.dk
Beskrivelse: Realtek RTL8139/810x Family Fast Ethernet NIC
Physical address: 00-0F-B0-FC-9C-32
DHCP activated: Yes.
Automatic configuration activated: Yes.
IP-Address: 87.58.149.226
Subnet-mask: 255.255.252.0
Standard gateway: 87.58.148.1
DHCP-server: 194.192.207.220
DNS-servers: 193.162.153.164
194.239.134.83

I'm not the big network wiz, so here is my ipconfig anyway. Btw, my dad told me that a while back our router got struck by lightning, and that's why we're using the first switch.

Does this indicate anything that's wrong with my internet?

SomeoneWithAPurpose · 2009-04-26 00:22:21

Oh damn.

I went downstairs to find out where the manuals for the router were... Turns out we don't have a router ...

All we have is 3 boxes; A internet phone adapter, a ethernet xDSL modem and a switch. Maybe this is why it's all ****ed up? Sorry for the misleading, but my dad always told me that we had a router. =\

Last edited by SomeoneWithAPurpose (2009-04-26 00:23:28)

Xyne · 2009-04-26 00:27:43

SomeoneWithAPurpose wrote:

IP-Address: 87.58.149.226

That confirms my suspicion.

I think I can explain the problem. Every computer that connects to a network needs an IP address. Normally you connect a router to the internet and the router gets a public IP address from the ISP's server. This is the address that people see when you connect to their sites. When you connect your computer to the router, the router gives you a different IP address. that only people on your LAN can see. The router can give several addresses because they are only used on the LAN, so you can connect multiple computers to it and each one can get a unique IP address. When you connect to the internet, your computers communicates with the router using private IP addresses on the LAN, then your router communicates with computers on the internet using public IP addresses.

In your case, your router is not configured to give out IP addresses. Instead, when you connect you are getting a public IP address directly from the ISP's server. Your ISP only has 2 public IP addresses that it can give you so that is why you cannot connect more than 2 computers at a time. You need to configure your router to act as a gateway between your LAN and the internet. To do this, you have to access the router's menu and set up a dhcp server (which gives out IP addresses on the LAN) along with a firewall and whatever else you need (your current setup makes your computer directly accessible from the internet which can be unsafe, especially when running Windows).

Oh damn.
I went downstairs to find out where the manuals for the router were... Turns out we don't have a router ...
All we have is 3 boxes; A internet phone adapter, a ethernet xDSL modem and a switch. Maybe this is why it's all ****ed up? Sorry for the misleading, but my dad always told me that we had a router. =\

Ah... yeah, that's a problem. What brand is the modem? Maybe it has some router functionality anyway.

Last edited by Xyne (2009-04-26 00:43:04)

SomeoneWithAPurpose · 2009-04-26 01:06:11

It's a Siemens Gigaset xDSL Modem.. It didn't say the model-name as far as I could see.

But yeah man, your theory sounds about right to me. I got my dad to order a router for us so we can get this network set up.

Arch Linux

#1 2009-04-25 22:43:22

Really weird network problem... Please help!

#2 2009-04-25 22:54:20

Re: Really weird network problem... Please help!

#3 2009-04-25 23:05:35

Re: Really weird network problem... Please help!

#4 2009-04-25 23:30:10

Re: Really weird network problem... Please help!

#5 2009-04-26 00:22:21

Re: Really weird network problem... Please help!

#6 2009-04-26 00:27:43

Re: Really weird network problem... Please help!

#7 2009-04-26 01:06:11

Re: Really weird network problem... Please help!

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