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Re: 2 NIC's

On Mon, 2021-07-05 at 16:39 +0200, tomas@tuxteam.de wrote:
> On Mon, Jul 05, 2021 at 04:13:07PM +0200, Nicolas George wrote:
> > tomas@tuxteam.de (12021-07-05):
> > > Yes: ip_forward should be 1.
> > 
> > Forwarding should not be necessary for connecting on the matching
> > IP
> > address. If ethA has IP-A and is connected to net-A and ethB has
> > IP-B
> > and is connected to net-B, then forwarding is not necessary to
> > connect
> > to IP-A from net-A nor to IP-B from net-B
> > 
> > Forwarding would  be necessary to connect to IP-A from net-B or IP-
> > B
> > from net-A without taking a round trip, but it also requires that
> > the
> > router on the networks knows about it.
> As I understood the OP, this is the ultimate goal. That said...
> > > Besides, and judging from the paragraph quoted above, your box
> > > seems
> > > to lose the route to the local network (192.168.xxx.xxx) once the
> > > other is connected.
> > 
> > If this is true, then this is the issue and forwarding is
> > irrelevant.
> ...this has to be taken care of first, definitely :)
> Cheers
>  - t

Dear All,

Thank you for the replies, I've learnt a lot about the workings of
Linux from these few emails.

The first question from Jeremy, the value of
/proc/sys/net/ipv4/ip_forward is 0, connecting to the thin client via
putty and using nano as an editor, it tells me I can't alter this
value, I am logged in as root.

The configuration of the network interfaces are all static, but from
the screen shot attached, it looks to me as though eth1 is trying to
use DHCP. Is this the issue?

Below is a sample of the /etc/network/interfaces file, I have been
trying routing in this file, this is currently #ed out.

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet static
	hwaddress ether 00:15:e9:4a:c8:81
	# dns-* options are implemented by the resolvconf package, if
	up ip route add dev eth0 table eth0
	up ip route add default via dev eth0 table eth0
	up ip rule add from table eth0
	up ip rule add to table eth0

# The secondary network interface
allow-hotplug eth1
iface eth1 inet static
	hwaddress ether 00:90:dc:07:28:91
	address 80.194.XX.XX/29
#	gateway 80.194.XX.XX
	up ip route add 80.194.XX.XX/29 dev eth1 table eth1
	up ip route add default via 80.194.XX.XX dev eth1 table eth1
	up ip rule add from 80.194.XX.XX/32 table eth1
	up ip rule add to 80.194.XX.XX/32 table eth1


Attachment: Screenshot_2021-07-06_06-16-24.jpg
Description: JPEG image

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