According to Ray Olszewski: While burning my CPU.
>
> Richard --
>
> Just wanted to correct a small misunderstanding (or get another response
> from you if I'm the one who is mistaken). You are correct that one almost
> never needs to recompile a kernel to get support for a specific Ethernet
> card, even when used as a second (or third or whatever) card.
I'm glad you have brought this up as i have never thought about mentioning
that, please read on.
>
> But all stock kernels I am familiar with come with IP forwarding disabled.
> Unless you enable IP forwarding (and I don't think this can be done as a
> module), the Linux server will itself be able to talk to hosts on either
> eth0 or eth1, but the server won't route traffic with origin on an eth0 host
> and destination on an eth1 host.
Correct, but wont 'cat 1 >/proc/sys/net/ipv4/ip_forward' change that anyway,
i remember reading about how Redhat init scripts have the ability to change
the default setting, thats with the standard script /etc/sysconfig/network.
(As of Redhat-5.0)
NETWORKING=yes
FORWARD_IPV4=false
So i "assume" that the standard kernel (In redhat anyway) has ip_forward
support.
When booting, /etc/rc.d/init.d/network is called, there is a whole script
passage for ip_forwarding.
Now i am not saying this all works out of the box, however like i said in
the start of the message i have read that redhat thought about this problem
and include a 'boot option', change FORWARD_IPV4=false FORWARD_IPV4=true
to as to it working i cant say as i have never used it.
Of course if people compile thier own kernel and leave it out then there
will be "no" support.
>
> It is for this reason that (I think) you need to do a kernel recompile -- I
> know I did need to do one when I actually set up a Linux E-to-E router, but
> that was about 2 years ago and things may have changed.
The todays name for it is;
CONFIG_IP_FORWARD
I will refrain from saying you dont need to "recompile", however i do
stronly belive that "if" redhat have gone to all the trouble of creating
init scripts to turn in on or off at bootime, then surely it is in the
"standard supplied kernel".
So its not realy a misunderstanding as such, its just that so many seem to
be using "the lastest and greatest" as its called thesedays.
O yes, it would have been a good idea if i had remembered to say something
like the above in the first place, i have an inclanation that i have (a long
time ago), as to it being on this list i cant remember.
I would certanly try the above before i recompled my kernel.
Of course i could be wrong.. I have been before.
>
>
> At 12:15 AM 1/12/99 +0000, Richard Adams wrote [with deletions]:
> >According to Ray Olszewski: While burning my CPU.
> >>
> >> If you do put 2 NICs in one PC, you'll need to configure 2 interfaces (eth0
> >> and eth1), use "cross-connect" cables to connect to the other 2 PCs (think
> >> of these as the Ethernet equivalent of modem eliminator cables on serial
> >> ports), and set up the Linux box to do IP forwarding so the other two PCs
> >> can comminucate with each other (this probably means compiling a custom
> kernel).
> >
> >The only need to recompile a kernel is IF the card is not supported by the
> >users kernel, or there is no module installed, normaly speaking a standard
> >distribution kernel (one from the distribtion cd's) has all drivers included
> >as modules. Its more a question of try it all first before we go compiling a
> >new kernel.
>
> ------------------------------------"Never tell me the odds!"---
> Ray Olszewski -- Han Solo
> 762 Garland Drive
> Palo Alto, CA 94303-3603
> 650.321.3561 voice 650.322.1209 fax [EMAIL PROTECTED]
> ----------------------------------------------------------------
>
--
Regards Richard.
[EMAIL PROTECTED]
Happy New Year, and may all your troubles be small (ones).
