iptables -A OUTPUT --set-mark , routing

iptables -A OUTPUT --set-mark , routing

[Dmitry Melekhov]

Hello!

I need to route traffic to specific port from localhost to specific gateway.

I'm testing this on icmp.

I wrote rules:

iptables -t mangle -A OUTPUT -p icmp -j MARK --set-mark 80
ip rule add prio 221 table 221 fwmark 80
ip route add default table 221 proto static  nexthop via 192.168.22.221 
dev eth0


Then I try to ping something from different subnet:

ping 10.1.1.1
connect: Network is unreachable


If I add rule
iptables -t mangle -A PREROUTING -p icmp -j MARK --set-mark 80

Then I can successefully ping 10.1.1.1 from another host (my host is 
default gw for it, it's address is 192.168.22.229).

Hmmm.

How can I route marked packets from localhost?

ping 10.1.1.1
PING 10.1.1.1 (10.1.1.1) from 192.168.22.254 : 56(84) bytes of data.
 From 192.168.22.229: icmp_seq=1 Redirect Host(New nexthop: 192.168.22.221)

Re: iptables -A OUTPUT --set-mark , routing

[George Alexandru Dragoi]

First, for marks, use hexa numbers, like --set-mark 0x80 and .. fwmark 0x80

I don;t know what proto static nexthop is, i dont use them :)
Make sure you did an ip route flush cache

On Wed, 21 Jul 2004 14:03:40 +0500, Dmitry Melekhov <dm@belkam.com> wrote:
> Hello!
> 
> I need to route traffic to specific port from localhost to specific gateway.
> 
> I'm testing this on icmp.
> 
> I wrote rules:
> 
> iptables -t mangle -A OUTPUT -p icmp -j MARK --set-mark 80
> ip rule add prio 221 table 221 fwmark 80
> ip route add default table 221 proto static  nexthop via 192.168.22.221
> dev eth0
> 
> Then I try to ping something from different subnet:
> 
> ping 10.1.1.1
> connect: Network is unreachable
> 
> If I add rule
> iptables -t mangle -A PREROUTING -p icmp -j MARK --set-mark 80
> 
> Then I can successefully ping 10.1.1.1 from another host (my host is
> default gw for it, it's address is 192.168.22.229).
> 
> Hmmm.
> 
> How can I route marked packets from localhost?
> 
> ping 10.1.1.1
> PING 10.1.1.1 (10.1.1.1) from 192.168.22.254 : 56(84) bytes of data.
>  From 192.168.22.229: icmp_seq=1 Redirect Host(New nexthop: 192.168.22.221)
> 
>