Using openSUSE 10.2 as a gateway for a local network

karnaf · 04-10-2007, 03:38 PM

OK, so I have an openSUSE 10.2 installed on my computer and it's connected to an ADSL router / modem (dsl0; Aztech ADSL 600E) directly (through ethernet card eth0)
I have another network card (eth1) which is connected to another computer (client, with Windows XP) with a crossover cable.

What I'm trying to do, is set the openSUSE computer to be the internet gateway for the client (WinXP) computer.

I've followed the instructions here - http://en.opensuse.org/SDB:DSL_Gatew..._8.0_or_Higher to the letter, and all things work fine, except for the last part where the client computer connects to the internet

Both computers have no problem pinging each other, and have no problems samba-accessing each other.

All network cards have static IPs for confortability (incl. the WinXP one)

netstat -rn output is:

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
212.143.205.235 0.0.0.0         255.255.255.255 UH        0 0          0 dsl0
192.168.2.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 eth1
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth0
127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo
0.0.0.0         0.0.0.0         0.0.0.0         U         0 0          0 dsl0

ifconfig output is:

Code:

dsl0      Link encap:Point-to-Point Protocol
          inet addr:89.138.68.24  P-t-P:212.143.205.235  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:266 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:16816 (16.4 Kb)  TX bytes:533 (533.0 b)

eth0      Link encap:Ethernet  HWaddr 00:19:D1:3D:6C:2A
          inet addr:192.168.2.22  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::219:d1ff:fe3d:6c2a/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:18982 errors:0 dropped:0 overruns:0 frame:0
          TX packets:17570 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:13083864 (12.4 Mb)  TX bytes:2539471 (2.4 Mb)
          Base address:0x30e0 Memory:50400000-50420000

eth1      Link encap:Ethernet  HWaddr 00:D0:B7:7F:0A:79
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::2d0:b7ff:fe7f:a79/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:225 errors:0 dropped:0 overruns:0 frame:0
          TX packets:402 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:31204 (30.4 Kb)  TX bytes:50360 (49.1 Kb)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:99 errors:0 dropped:0 overruns:0 frame:0
          TX packets:99 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:6632 (6.4 Kb)  TX bytes:6632 (6.4 Kb)

content of /etc/sysconfig/network/routes is

Code:

default 192.168.0.1 - -

According to the ADSL router manufacturer, and the ISP's info, the ADSL router's gateway IP should be 10.0.0.138, but it doesn't show that anywhere, and trying to config that as the default server or trying to ping it does nothing

I saw some other papers about this issue, and they claim I'm supposed to have some line in the netstat -rn that goes like this

Code:

0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth0

but I don't

Sorry for the long post

Any clues?

Thanks!
karnaf

rtspitz · 04-10-2007, 05:00 PM

why do you have the DSL0 interface running if your linux-box is connected to a DSL-ROUTER-BOX ??

if you really have a dsl-router-box it should come with a web-interface accessible with sth like http://192.168.1.1, this IP must be set as default gateway + dns server on all clients.

in case you just have a dsl-modem the linux-box needs to be the router/default-gateway for the rest of the network. you can do this by enabling so called masquerading/NAT (ethernet interface for internal network) with yast + firewall. dns resolution can be done with your provider's servers if they stay the same, or just run BIND yourself.

karnaf · 04-11-2007, 01:01 PM

I guess it's an ADSL modem and not a router because I can't access its web interface, even when trying the default IP given by the manufacturer. Could be the provider had limited its capabilities. The unit itself says "Aztech ADSL2+ Ethernet Bridge Router DSL-600E" so I assumed it was a router, but I know that some infrastructure providers limit their units' capabilities.

I've enabled masquerading long ago, but it didn't help (YaST -> Firewall -> Masquerading -> X Masquerade Networks). I've also set the DNS IPs to be the static ones provided by the ISP on both computers.

It can't be the internet connection (because the linux machine connects properly)
It can't be the connection between the computers (because they ping and browse each other)
I assume it is something with the routing mechanism (from the client to the world through the server) but I'm sort of clueless about what's wrong there.

Any more suggestions of places to look at?

Thanks!!!
karnaf

karnaf · 04-11-2007, 01:24 PM

It's working!!!

I went over all the configuration again (and again) and read a few more articles about the issue and realized the default gateway IP I defined was the wrong one. I had set it to be the IP of the network card that is used for the internal network (192.168.0.1), instead of the one used to go to the outer world (192.168.2.22).

At least I think that's what had solved the problem.

Thanks!
karnaf

p.s. another nice article that had helped a bit and deserves credit http://www.freesoftwaremagazine.com/...way?page=0%2C0

karnaf · 05-19-2007, 11:05 AM

Now that I've managed to config it all, how can I find out what is my modem / router's manager web interface address?

According to the manual, it's 10.0.0.138, and if I boot in Windows, this IP works, but trying that IP when booted as OpenSUSE fails. I've tried several addresses that are standard (e.g. 192.168.1.1 and 10.0.0.2) and still nothing.

Maybe I'm supposed to define that somehow myself?

Any ideas?

Thanks.

drokmed · 05-25-2007, 10:39 AM

traceroute www.yahoo.com

That will show you each hop from your local PC to that website. If your modem is actually routing IP, and doesn't ignore pings, you should see it's IP address.

You can always call your dsl provider's tech support too!

EDIT: If your dsl modem is in just transparent bridging mode and not routing, it might not have an IP address accessible.

auxsvr · 05-25-2007, 11:31 AM

Could you post netstat -rn again? Can you ping the default gateway IP address?

karnaf · 05-29-2007, 04:20 PM

here's the netstat -rn again

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
212.143.205.244 0.0.0.0         255.255.255.255 UH        0 0          0 dsl0
192.168.2.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 eth1
192.168.79.0    0.0.0.0         255.255.255.0   U         0 0          0 vmnet1
172.16.25.0     0.0.0.0         255.255.255.0   U         0 0          0 vmnet8
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth0
127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo
0.0.0.0         0.0.0.0         0.0.0.0         U         0 0          0 dsl0

No problem pinging the default GW - 192.168.2.22

Quote:

If your dsl modem is in just transparent bridging mode and not routing, it might not have an IP address accessible.

If that were the case, then I assume I wouldn't have been able to access it when using WinXP as well, no?

Thanks

auxsvr · 05-30-2007, 06:24 PM

Doesn't your modem have a DHCP server? If it has, it will automatically configure the default route and you won't need to mess with it. You'd better avoid configuring static routes if you don't know what you're doing.