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I got three gateways: on eth0  (default), on eth0:0 on eth0:1

I'm trying to make my computer decide on which to use, from the request port. (request comes server-side) -> via  to -> via to -> via to

how should I proceed ?


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Do you have three gateways, or three IP addresses? – womble Jul 14 '12 at 11:28
both. gateways are 192.168.X.1, and IPs are 192.168.X.200 – user1219721 Jul 15 '12 at 1:21
up vote 1 down vote accepted

You should mark the traffic with iptables first, then you can set rules to handle the traffic accordingly, something along this lines:

iptables -A PREROUTING -p tcp --dport 80 -t mangle -j MARK --set-mark 1
iptables -A PREROUTING -p tcp --dport 81 -t mangle -j MARK --set-mark 2
iptables -A PREROUTING -p tcp --dport 82 -t mangle -j MARK --set-mark 3

ip rule add fwmark 1 table 1
ip rule add fwmark 2 table 2
ip rule add fwmark 3 table 3

ip route add default via table 1
ip route add default via table 2
ip route add default via table 3

Of course next hop needs to handle NAT/etc and I didn't check syntax.

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