Re: [SLE] Routing

From: Jim Cunning (jcunning_at_cunning.ods.org)
Date: 03/16/04

  • Next message: qrn_Hansen?=: "Re: [SLE] x86-64 Questions" 
    Date: Tue, 16 Mar 2004 09:41:24 -0800 (PST)
To: suse-linux-e@suse.com

    Tuesday Mar 16 at 5:11pm, Vince Littler wrote:
    > On Tuesday 16 March 2004 2:42 am, Paul W. Abrahams wrote:
    > > On Monday 15 March 2004 12:07 pm, Vince Littler wrote:
    > > > Try <Yast2>-<Network Services>-<Routing>. Enable IP Forwarding.
    > >
    > > Any advice on when it is, and isn't, appropriate to turn on IP Forwarding?
    > >
    > > Paul Abrahams
    >
    > Is: when you want to do routing
    >
    > Isn't: when you don't
    >
    > Less tersely put, the routing table on a machine applies to data originating
    > on that machine and is the means by which the machine routes its own traffic
    > to the appropriate interface [usu. eth0]. In this sense, even a single
    > interface workstation is a router - it must know when to put stuff to another
    > node on its subnet and when to send stuff to its router, even though it all
    > goes out of the single interface.
    >
    > However, if you don't turn on IP forwarding, a router with a valid routing
    > table will still only route its own traffic - to the appropriate interface
    > for either [any] of its subnets and to its neighbouring router[s]. Once IP
    > forwarding is enabled, it will do the same for stuff arriving at its network
    > interfaces from elswhere.

    Vince's answer may be a little obtuse for newbies, so I'll add my $.02:

    * If you have more than one PC in your local network but only one directly
    connected to the internet, then that system is a router and must have IP
    forwarding enabled. All traffic from your other system(s) must go through
    that system to and from the internet.

    * If you have multiple PCs on a single local network all connected to a
    router (such as a DSL router/firewall), then none of the PCs need to have
    IP forwarding enabled.

    Jim 

    -- 
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