I'm sure you can solve this

I'm sure you can solve this

[decompose]

Hi Ive read the docs and still can't work it out (Yes I'm stupid)

Background: I want to forward traffic from hosts on the switch to 
through router A to router B. (and later from router B to a host on the 
switch, but i guess I could just invert the first problem).

I think one of the reasons i'm having trouble with this is because all 
hosts are on the same subnet (here is the setup)

[switch]-->[router A]-->[router B]-->(Inet)
         192.168.0/24

Ive tryed various things this being one of them (where x is a host on 
the switch)
iptables -t mangle -A POSTROUTING -p tcp -s 192.168.0.x -d 192.168.0.223 
--destination-port 80

I hope my question is clear enough. Thanks in advance

RE: I'm sure you can solve this

[Daniel Chemko]

Firstly, what benefit are you trying to get from having multiple jumps
on the same subnet? It seems needlessly complicated.
You can 'bounce' off an interface with some dirty work. Example:

# Redirect all traffic coming from 192.168.1.* to 192.168.1.222,
assuming that 192.168.1.222 is the default gateway for this gateway. I
am assuming the internal IP address of this computer is 192.168.1.200

# You don't need the mark, but what the hell, its there if you like it
:-)
iptables -t mangle -A PREROUTING -s 192.168.1.0/16 -j MARK --set-mark
222
iptables -t nat -A POSTROUTING -d 192.168.1.222 -m mark --mark 222 -j
SNAT --to 192.168.1.200
# Allow in-out forwarding if using locked down FORWARD chain
iptables -t filter -A FORWARD -i eth1 -o eth1 -j ACCEPT


Mind you, because of the SNAT, you have to drop the benefit of knowing
the source address at the second gateway.

-----Original Message-----
From: decompose [mailto:decompose@orcon.net.nz] 
Sent: Wednesday, March 31, 2004 10:47 PM
To: netfilter@lists.netfilter.org
Subject: I'm sure you can solve this


Hi Ive read the docs and still can't work it out (Yes I'm stupid)

Background: I want to forward traffic from hosts on the switch to 
through router A to router B. (and later from router B to a host on the 
switch, but i guess I could just invert the first problem).

I think one of the reasons i'm having trouble with this is because all 
hosts are on the same subnet (here is the setup)

[switch]-->[router A]-->[router B]-->(Inet)
         192.168.0/24

Ive tryed various things this being one of them (where x is a host on 
the switch)
iptables -t mangle -A POSTROUTING -p tcp -s 192.168.0.x -d 192.168.0.223

--destination-port 80

I hope my question is clear enough. Thanks in advance