Re: How to masquerade when using ROUTE

[Glaucius Djalma Pereira Junior <glaucius@gmail.com>]

take a look in  iproute2,

lartc.org  , using  iptables and iproute to do it 

1) create an entry in /etc/iproute2/rt_tables

echo "200            fabian

2) create the route default to route fabian
ip route add default via x.x.x.x dev ethX table fabian

3) create the rules 

iptables -t mangle -A PREROUTING -p tcp --dport 25 -j MARK --set-mark 3

4) routing the packets 

ip rule add from fwmark 3 lookup fabian prio 1


be happy 



On 5/7/05, Fabian Wolter <netfilter-ml@fabian-wolter.de> wrote:
> Hi,
> 
> I want to route all outgoing port-25-traffic produced by the clients
> over ppp1. The rest schould take the default route over ppp0.
> 
> I used the following command:
> 
> iptables -A PREROUTING -p tcp --dport 25 -t mangle -i eth0 -j ROUTE
> --oif ppp1
> 
> But the source addresses of the packets are wrong as "tcpdump -ni ppp1"
> shows:
> 
> 01:20:24.422756 IP 192.168.0.4.32825 > 160.45.10.13.25: S
> 2020082843:2020082843(0) win 5840 <mss 1460,sackOK,timestamp 266850[|tcp]>
> 
> 192.168.0.4 is the IP adress of the client which tried to connect to the
> mailserver 160.45.10.13.25.
> 
> Masquarding is done to 192.168.0.0/24:
> 
> # iptables -t nat -L POSTROUTING
> Chain POSTROUTING (policy ACCEPT)
> target     prot opt source               destination
> MASQUERADE  all  --  192.168.0.0/24       anywhere
> 
> My default route is set to ppp0.
> 
> So, how can I replace/masquerade the 192.168.0.4 by the official IP
> address of ppp1?
> 
> Regards,
> Fabian
> 
> 


-- 
Glaucius Djalma Pereira Junior
glaucius@gmail.com