Network forwarding - both directions

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10-21-2007
MKas

Network forwarding - both directions

Hello,

My network configuration:

1st pc.
eth0 - local area (192.168.0.1)
eth1 - internet
iptables -t nat -A POSTROUTING -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward

2nd pc.
eth0 - 192.168.2.1 \
eth1 - 192.168.1.1 / sharing internet to local area network

eth2 - 192.168.0.2 -> getting internet from 1st pc.
iptables -t nat -A POSTROUTING -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward

3rd pc.
eth0 - 192.168.1.2 -> getting internet from 2nd pc.

The problem is:
from 3rd pc I can ping all ips in network, but from 1st pc I can ping only 192.168.0.2. I don't see even "192.168.1.1"

Why I need that? I want to redirect xxx port from 1st pc to 3rd pc.

Any ideas?
10-22-2007
LlNUX

>but from 1st pc I can ping only 192.168.0.2. I don't see even "192.168.1.1"
> Any ideas?
I assume that you have mask 255.255.255.0 :

1PC: 192.168.0.1\24 network 192.168.0.0
2PC: 192.168.2.1\24 network 192.168.2.0
- 192.168.1.1\24 network 192.168.1.0

My fist guess is that PC1 and PC2 are on different networks so can not sees each other.

hope this helps
10-23-2007
MKas

Then why I see pc1 from pc3?

It looks like:

internet <- eth1-pc1-eth0 <-> eth2<-| pc2-eth1 <-> eth0-pc3
pc3 see - pc2 all eths, pc1 all eths
pc2 see - pc3 eth, pc1 all eths
pc1 see - only pc2 eth2
10-28-2007
rossonieri#1

Quote:

Originally Posted by MKas

Hello,

My network configuration:

1st pc.
eth0 - local area (192.168.0.1)
eth1 - internet
iptables -t nat -A POSTROUTING -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward

The problem is:
from 3rd pc I can ping all ips in network, but from 1st pc I can ping only 192.168.0.2. I don't see even "192.168.1.1"

Why I need that? I want to redirect xxx port from 1st pc to 3rd pc.

Any ideas?

this will be a very long answer :)
your pc1 having a default route 0/0 via eth1.
any route will be forward to that interface.
try add static route to 1.0/24 and 2.0/24 network via their respective interface.
and modify your -t nat statements (both on pc1 and pc2) to include only nat-ed interface :
ipt -t nat -I POSTROUTING -o <internet_intf> bla bla...

why?
so that your interfaces wont get nat-ed all of them.

HTH.