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I want to change this:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
178.212.120.5   192.168.1.254   255.255.255.255 UGH   0      0        0 eth2.2
208.67.222.222  192.168.1.254   255.255.255.255 UGH   0      0        0 eth2.2
192.168.1.0     *               255.255.255.0   U     0      0        0 eth2.2
192.168.10.0    *               255.255.255.0   U     0      0        0 br0
239.0.0.0       *               255.0.0.0       U     0      0        0 br0
default         192.168.1.254   0.0.0.0         UG    0      0        0 eth2.2

into this:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
178.212.120.5   192.168.1.254   255.255.255.255 UGH   0      0        0 ra0
208.67.222.222  192.168.1.254   255.255.255.255 UGH   0      0        0 ra0
192.168.1.0     *               255.255.255.0   U     0      0        0 ra0
192.168.10.0    *               255.255.255.0   U     0      0        0 br0
239.0.0.0       *               255.0.0.0       U     0      0        0 br0
default         192.168.1.254   0.0.0.0         UG    0      0        0 ra0

and configure NAT the way that:

  1. Public NAT interface is ra0 with IP 192.168.1.3
  2. NAT internal subnet is 192.168.10.0/24 on br0

The problem I got is that I know how to use Linux route and ifconfig commands but I know nothing about iptables.

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up vote 0 down vote accepted

A "rough and ready" answer would be to use route and ifconfig to set up the ra interface and routing, and then issue an iptables command -

/sbin/iptables -t nat -I POSTROUTING -o ra0 -j MASQUERADE

This will masquerade (all) traffic going out ra0 but not br0. I note however that the "NAT interface of ra0 is not actually a real world IP address, so either you will be doing double nat or that IP address is incorrect.

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