Re: Multiple Network Gateways
[Before going with the rest of the reply, I'd like to thank who (lee,
William Hopkins, Johannes Obermueller, Bonno Bloksma, Andrew McGlashan,
Camaleón) sincerely answered to my question.]
On Fri, 15 Jul 2011 23:31:05 +0200, "Bonno Bloksma" writes:
> In here you have some duplicate information that is not needed. In the eth0
> section the netmask 255.255.255.240 together with the ip-address of 10.10.98.100
> automaticaly defines the network and broadcast address you give in the next
> lines. You can leave them out.
They are added by the Debian installer, not me. But yep, you are right.
> A gateway statement means: send ANYTHING for which there is no specific route in
> the routing table to this address which can be reached via this interface. There
> is usualy just one gateway statement in the entire interfaces file unless one
> wants to do multiple gateway routing, which is usualy done with the more
> flexible and sophosticate ip statement.
>
> So the gateway statement in the eth1 section is what causes the problem. You do
> NOT want the gateway statement there as that is NOT the address to send all
> unspecified traffic to, that is what you want the eth0 interface to use the
> 10.10.98.110 address for.
>
> The address and netmask statement together define which network is behind the
> eth1 interface and which traffic should be send to the network behind that
> interface. In this case that will automaticaly be all trafic for
> 192.168.100.0/24, that is all trafic for 192.168.100.*
So you mean that, via a configuration as follows
--8<---------------cut here---------------start------------->8---
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 10.10.98.100
netmask 255.255.255.240
gateway 10.10.98.110
dns-nameservers 10.10.10.11 10.10.10.12
dns-search ozun.int
auto eth1
iface eth1 inet static
address 192.168.100.100
netmask 255.255.255.0
--8<---------------cut here---------------end--------------->8---
all of my 192.168.100.0/24 traffic will be routed through eth1. But the
thing I don't understand here is that: Say I typed "ping 192.168.100.1".
How will it know that it will need to use 192.168.100.98 as a gateway to
192.168.100.1?
> You also have some dns lines in that interfaces file. As far as I know that is
> not alowed and those lines should be in the /etc/resolv.conf file.
Yep, /etc/resolv.conf solves the issue in a static manner, but the dns-*
parameters I used in interfaces(8) are provided by the resolvconf
package.
Best.
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