Mailinglist Archive: opensuse (3964 mails)

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Re: [SLE] Two NICs
  • From: Stan Glasoe <SRGlasoe@xxxxxxxxxxx>
  • Date: Sun, 7 Nov 2004 12:53:40 -0600
  • Message-id: <200411071253.40426.SRGlasoe@xxxxxxxxxxx>
On Saturday 06 November 2004 11:09 pm, Don Parris wrote:
> eth0 is my DSL connection - should have made that clear. eth1 Goes
> to the local hub.
> snipped <
> So far, I've been switching the DSL & LAN cables on eth0 as
> needed to connect to the internet or to the LAN. While this
> defintely cuts down outsiders' chances of attacking the whole
> LAN, it is inconvenient. ;)
You shouldn't have to do that manual switching of cables. Leave the
cables all connected where they are supposed to go. With both
interfaces cabled and up and running, do an 'ifdown eth0' (from a root
prompt in a konsole/console) to test just eth1 on your internal LAN.
This allows you to dictate which NIC is talking to which network and
when. Then to test the Internet side do an 'ifdown eth1' and then an
'ifup eth0' to test just external/Internet connectivity from this

Without setting up the connection/route between the cards with "Enable
IP Forwarding" you have to work with only one card at a time. I believe
that without the routing setup that all traffic will most likely go to
the first NIC available - sometimes - which makes troubleshooting and
expecting certain results diabolically threatening to one's
sanity/sobriety. Either that or its just my luck!

There's a nice little program called KNemo that puts a little network
icon in the systray area (and also appears within KDE Control Center);
one for each connection you have on the machine. Label them and then
you'll know which is up/down with a glance or mouse over.
> As mentioned in my response to Anders, I can get VNC connections
> using the LAN cable on eth0, but when using eth1, I get nada. Ok, I
> do get blinking lights - but that's about it.
But IF I understand what you've been doing you connect both cables to
the same hub once in a while. Or you disconnect eth1 from the hub when
you connect eth0 to the hub. Stop that. See above.
> > Remember to turn on "Enable IP Forwarding" for NICs in Yast,
> > Network Devices, Network Cards.
> If it's o.k. with you, I'd like to get eth1 working with the local
> hub first - then worry about giving my LAN access to the outside
> world.
Well, that's fine if you don't like to be totally confused. Good plan.
That's why you need to start turning off NICs via ifup/ifdown and
checking status via 'ifconfig -a' instead of swapping cables.

> > > --
> Don


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