Two NICs, Two gateways, One Ubuntu

Clown

Clown

Clown

Soldato
Joined
13 Apr 2004
Posts
5,086
Location
London
I have two ISPs and two routers - 192.168.0.1 and 192.168.0.11.
My server box is permanently on but at the moment it is only connected to one router at a time. Is it possible to connect up both network cards in my server, each one with it's own gateway, and have one as a backup in case one gets disconnected?
 
I have a little bit more information about my set up -
R1 (Netgear DG834N, ADSL Be Internet): 192.168.0.1
R2 (D-Link DIR655, Cable Virgin Media): 192.168.0.11

Ubuntu Box:
eth1 - 192.168.0.3, default gw 192.168.0.11
eth2 - 192.168.0.33, default gw 192.168.0.1

I hope that makes sense.
Now I want the Ubuntu box to mainly use the internet from 192.168.0.11.
I just want it to be connected to both ISPs because, well, why not? :)

That website looks very useful, I'll revise it when I get home. Cheers!
 
I like my wireless-N too much, and between them my two routers cost about £200. I don't think I'm rich enough to dump them :)
4.2.1. Split access
The first is how to route answers to packets coming in over a particular provider, say Provider 1, back out again over that same provider.

Let us first set some symbolical names. Let $IF1 be the name of the first interface (if1 in the picture above) and $IF2 the name of the second interface. Then let $IP1 be the IP address associated with $IF1 and $IP2 the IP address associated with $IF2. Next, let $P1 be the IP address of the gateway at Provider 1, and $P2 the IP address of the gateway at provider 2. Finally, let $P1_NET be the IP network $P1 is in, and $P2_NET the IP network $P2 is in.

One creates two additional routing tables, say T1 and T2. These are added in /etc/iproute2/rt_tables. Then you set up routing in these tables as follows:

ip route add $P1_NET dev $IF1 src $IP1 table T1
ip route add default via $P1 table T1
ip route add $P2_NET dev $IF2 src $IP2 table T2
ip route add default via $P2 table T2
Click to expand...
I tried doing this, but I didn't know what I would put as $P1_NET. Also I wasn't sure if all I was meant to do was add this in the bottom of /etc/iproute2/rt_tables or what.

Sorry to be a pain :(
 
Here's my set-up:
http://www.clowneh.co.uk/network.txt
Code: 
root@Server:/home/clown# ip address list
1: lo: <LOOPBACK,UP,10000> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth2: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0e:a6:4c:6b:a9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.33/24 brd 192.168.0.255 scope global eth2
    inet6 fe80::20e:a6ff:fe4c:6ba9/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0e:a6:54:77:da brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.3/24 brd 192.168.0.255 scope global eth1
    inet6 fe80::20e:a6ff:fe54:77da/64 scope link
       valid_lft forever preferred_lft forever
root@Server:/home/clown# ip route show
192.168.0.0/24 dev eth2  proto kernel  scope link  src 192.168.0.33
192.168.0.0/24 dev eth1  proto kernel  scope link  src 192.168.0.3
169.254.0.0/16 dev eth2  scope link  metric 1000
default via 192.168.0.11 dev eth1  metric 100
default via 192.168.0.1 dev eth2  metric 100

I don't really know what I'm doing or what to change :)
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom