LARTC - Jul 2005 - multiple uplinks works on linux router but not on clients

Hello,
I''m trying to achieve the following.
2 ISP''s and 1 LAN with failover. So, when 1 internet connection fails
the other need to take over. I''m aware of the restrictions. The current
sessions are lost.
I did this before, one and a half year ago or something. But at that router
wasn''t failover. Now i''ve read the nano howto and followed it.

I''m using Debian with kernel 2.6.12-3 patched with Julian
Anastasov''s routes patch. This integrated failover functionality. I
need to say. It works great on the machine itself. Everytime I start a
traceroute another link will be used. When I unplug an internet link, all of my
traceroutes uses the internet connections which are up. When I re-plug the
internet link my traceroutes will use the one again.
This is how it needs to be, also for the connected pc''s. But
that''s not working. All traceroutes on client machine are going through
the same router: 192.168.20.1->192.168.32.1->internet

I used following firewall rules, but that shouldn''t be the problem:
iptables -t filter -N keep_state
iptables -t filter -A keep_state -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -t filter -A keep_state -j RETURN

iptables -t nat -N keep_state
iptables -t nat -A keep_state -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -t nat -A keep_state -j RETURN

iptables -t nat -A POSTROUTING -o eth1 -s 192.168.20.0/24 -j SNAT --to
192.168.1.240
iptables -t nat -A POSTROUTING -o eth2 -s 192.168.20.0/24 -j SNAT --to
10.0.0.240
iptables -t nat -A POSTROUTING -o eth3 -s 192.168.20.0/24 -j SNAT --to
192.168.32.240

iptables -t nat -A PREROUTING -j keep_state
iptables -t nat -A POSTROUTING -j keep_state
iptables -t nat -A OUTPUT -j keep_state
iptables -t filter -A INPUT -j keep_state
iptables -t filter -A FORWARD -j keep_state
iptables -t filter -A OUTPUT -j keep_state

It looks like the problem comes from my multi route table 222. When I change the
order of the devices in the multiroute rule all of my traceroutes on the clients
are using the last nexthop via. I''m using three eth''s as
external interfaces and always the last one in my multihop route will be used by
my workstations.
Setup:
ip rule ls
0:      from all lookup local
50:     from all lookup main
201:    from 192.168.1.0/24 lookup 201
202:    from 10.0.0.0/24 lookup 202
203:    from 192.168.32.0/24 lookup 203
222:    from all lookup 222
32766:  from all lookup main
32767:  from all lookup default

 ip ro s t 222
default  proto static
        nexthop via 192.168.1.1  dev eth1 weight 1
        nexthop via 10.0.0.138  dev eth2 weight 1
        nexthop via 192.168.32.1  dev eth3 weight 1

ip ro s t 201
default via 192.168.1.1 dev eth1  proto static  src 192.168.1.240
prohibit default  proto static  metric 1

ip ro s t 202
default via 10.0.0.138 dev eth2  proto static  src 10.0.0.240
prohibit default  proto static  metric 1

ip ro s t 203
default via 192.168.32.1 dev eth3  proto static  src 192.168.32.240
prohibit default  proto static  metric 1

Well, I think you have all the information. What I want to do is simply routing
on multiple interfaces. No queue based routing or something. Linux may just
choose which route is going to be used.

Thanks for your help in advance.
Kind regards,
Hans Middelhoek
Netherlands

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Hi,
I''ve been testing the whole time and found some interesting
information.
Obviously I haven''t compiled the kernel very well. I booted the machine
in
it''s old kernel, 2.6.8-2 and now the pc''s in my network are
using all
internet interfaces. I see that with a traceroute. What did I do wrong in 
compiling and patching the kernel. Probably I missed an important setting in 
the kernel configuration, but which? It''s the first time for me I
compiled a
kernel and it was very though to have it working. I got a lot of errors 
during the first tries. Later on, compiling succeeded without any errors, so 
I thought it was working fine.
I can see that the patch applied, because failover works, but there is 
something else what doesn''t work ad it should.
Who understand this strange problem? thnx.