Prev: What is the minimum reverse network that can be delegated?
Next: What is the proper ownership, group and permission for the files under /var/named?
From: Prashant Jois on 15 Jul 2010 15:30
Hi,

I'm not sure if this is the appropriate forum on which to post this
question. Feel free to direct me to a more appropriate venue if this
is the case. I should mention too that I'm a bit of a novice when it
comes to networking.

I have two internet connections through two different ISPs, let's call
them IA and IB. I have one server with two NICs (LAN and WAN) that I
want to use as a firewall machine and for load balancing/failover.
This is the scenario I want to set up:

IA,IB <------> (switch) <------> WAN(server)LAN<-------->

The switch is not VLAN or managed, just a simple switch. IA and IB
are accessible on the 192.168.30.0/24 and 192.168.40.0/24 networks,
with gateways 192.168.30.1 and 192.168.40.1 respectively.

Is is possible to set the server up such that I can access both IA and
IB through my one single WAN NIC?

I thought of perhaps setting the WAN NIC's main address to be in the
192.168.30.0/24 network, then setting up a virtual interface on the
same card to be in the 192.168.40.0/24.

My /etc/network/interfaces (on Ubuntu) would look something like this:

auto lo
iface lo inet loopback

# LAN
auto eth0
iface eth0 inet static
address 192.168.1.101
netmask 255.255.255.0

# Primary WAN
auto eth1
iface eth1 inet static
address 192.168.30.101
netmask 255.255.255.0

# Secondary WAN
auto eth1:1
iface eth1:1 inet static
address 192.168.40.101
netmask 255.255.255.0

However, this scenario does not work as expected. I'm unable to see
the 192.168.40.0/24 network at all.

Is there any way to achieve what I want using a single WAN NIC like I
described?

Thanks for any help
From: Pascal Hambourg on 15 Jul 2010 18:48
Hello,

Prashant Jois a �crit :
>
> I have two internet connections through two different ISPs, let's call
> them IA and IB. I have one server with two NICs (LAN and WAN) that I
> want to use as a firewall machine and for load balancing/failover.
> This is the scenario I want to set up:
>
> IA,IB <------> (switch) <------> WAN(server)LAN<-------->
>
> The switch is not VLAN or managed, just a simple switch. IA and IB
> are accessible on the 192.168.30.0/24 and 192.168.40.0/24 networks,
> with gateways 192.168.30.1 and 192.168.40.1 respectively.
>
> Is is possible to set the server up such that I can access both IA and
> IB through my one single WAN NIC?

Sure.

> I thought of perhaps setting the WAN NIC's main address to be in the
> 192.168.30.0/24 network, then setting up a virtual interface on the
> same card to be in the 192.168.40.0/24.

You don't even need a separate subnet for each ISP.

> My /etc/network/interfaces (on Ubuntu) would look something like this:
>
> auto lo
> iface lo inet loopback
>
> # LAN
> auto eth0
> iface eth0 inet static
> address 192.168.1.101
> netmask 255.255.255.0
>
> # Primary WAN
> auto eth1
> iface eth1 inet static
> address 192.168.30.101
> netmask 255.255.255.0
>
> # Secondary WAN
> auto eth1:1
> iface eth1:1 inet static
> address 192.168.40.101
> netmask 255.255.255.0

Note that eth1:1 is not a virtual interface but just an IP alias on
eth1. From the point of view of the kernel, routing, iptables... (things
that matter), eth1:1 does not exist as an interface.

> However, this scenario does not work as expected. I'm unable to see
> the 192.168.40.0/24 network at all.

Can you elaborate ?
What is the output of ip addr or ifconfig and ip route or route -n ?

> Is there any way to achieve what I want using a single WAN NIC like I
> described?

Sure. This is one. AFAIK it should work.
 | 
Pages: 1
Prev: What is the minimum reverse network that can be delegated?
Next: What is the proper ownership, group and permission for the files under /var/named?