configuring the sequence order of access of web connections

billcarson · 06-08-2008, 07:19 AM

My openSUSE 10.3 box runs ethernet to both a DSL and cable modem.

I would like to control which these (eth 0, or eth 1) will be the default modem to access the web.

XP accomplishes this with the "Advanced Settings" buried under Network connections where you can change the list priority.

Anything similar in Linux /openSUSE 10.3?

thanks.

MensaWater · 06-08-2008, 10:19 AM

You can use iptables to configure network connections (firewall, port blocking, and NATting) so I imagine it could be configured for this purpose. Doing some checking for iptables how-tos may give you an idea.

billcarson · 06-12-2008, 06:39 AM

Thanks.

Yeah, the IP tables; I was afraid someone might mention these. They look real complicated. I guess if you really want to do some serious package management then you have to learn IP table configuration.

Actually, I am surprised there is not a preference setting somewhere for something as simple as OFF/ON for either eth 0 or eth1 connection to the web.

Bill

lsteacke · 06-12-2008, 07:34 AM

There are ways to bring up and down your ethernet interfaces, and there are also ways to change the default route for packets travelling out of those interfaces. I'd imagine having 2 internet connections has something to do with maintaining connectivity at all times. To bring the interfaces up and down try

Code:

ifdown eth0

and

Code:

ifup eth0

As far as the default routes are concerned if you want to attempt this, you could post the output of a couple commands and we could possibly help you with this.

Code:

ifconfig -a

Code:

route -n

MensaWater · 06-12-2008, 08:51 AM

Quote:

Actually, I am surprised there is not a preference setting somewhere for something as simple as OFF/ON for either eth 0 or eth1 connection to the web

That makes it sound like you want to turn off eth0 or eth1 so they don't automatically start which isn't how I understood your original question.

As the person above notes you can disable interfaces with ifconfig.

You can also setup the default as to whether the specific interface starts or stops (on or off as you put) it. Not sure where that is on SUSE. On RedHat Linux it is /etc/sysconfig/network-scripts. There one would find ifcfg-eth0, ifcfg-eth1 etc... Within each of those files is a flag ONBOOT=yes - simply setting it to ONBOOT=no would prevent it from starting networking on the interface in the file name.

billcarson · 06-14-2008, 12:37 PM

Well, the actual basis for this question is that I pay a lot for really high speed cable web access (downloading images, etc)

Either eth0 or eth1 is being used as a LAN connection to other computers and also supports a slower DSL connection.

I don't need the high speed on the LAN, but do on the web. And I need both on at the same time.

So if looks like eth0 is accessing the internet but how can you determine if this is actually the high speed cable modem?

ifconfig -a shows

Code:

eth0      Link encap:Ethernet  HWaddr 00:11:D8:82:A5:E6  
          inet addr:192.168.2.3  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::211:d8ff:fe82:a5e6/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:14825 errors:0 dropped:0 overruns:0 frame:0
          TX packets:13028 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:10935214 (10.4 Mb)  TX bytes:2523599 (2.4 Mb)
          Interrupt:21 Base address:0xa000 

eth1      Link encap:Ethernet  HWaddr 00:11:D8:82:A1:F2  
          inet6 addr: fe80::211:d8ff:fe82:a1f2/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:432 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:27648 (27.0 Kb)  TX bytes:492 (492.0 b)
          Interrupt:17 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0

route -n shows

Code:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.2.0     0.0.0.0         255.255.255.0   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         192.168.2.1     0.0.0.0         UG    0      0        0 eth0

lsteacke · 06-17-2008, 03:41 PM

Well aside from tracing the physical cable back to the actual modem, you could possible test your bandwidth at a website to make sure you are getting the throughput you require. For this I usually query http://www.speakeasy.net/speedtest As far as I can tell from your output, I am fairly certain that eth0 is your high bandwidth interface.