Oh... I was wrong.... You do have a masquerade rule.

So... can you ping using ip addresses?

from my laptop, i cant ping the gateway ip address, and for sure i can ping my laptop ip address.


what gateway IP address should i set in the laptop?should i choose to use the "Obtain IP address Automatically"??

i think that is a command where i can see whether there is any packet flow through my Linux box bridge, is it??
what commnad is that???
is it neccessary?

Your laptop's gateway will be the PCs ip of the interface connected to the laptop..... that is the only IP address available to your laptop to get to the internet.

I'm not sure (because you said AND instead of BUT in your sentence) if you can ping the PC's gateway (that would be the router) from your laptop. Can you?

Take a look at this thread. It has the main points in a very simple fashion. Perhaps I'm not being clear (or simple) enough:

http://www.linuxquestions.org/questi...hreadid=274625

The basic setup of a bridge is done like:
Zero IP the interfaces. The bridge needs the network devices to be operational, but without TCP/IP running on them.
# ifconfig eth0 0.0.0.0
# ifconfig eth1 0.0.0.0
Create the bridge interface.
# brctl addbr mybridge
Add interfaces to the bridge.
# brctl addif mybridge eth0
# brctl addif mybridge eth1
Put up the bridge.
# ifconfig mybridge up


so the Pc's eth1 ip address is set to 0.0.0.0
i dont think i can set the gateway ipaddress for my laptop to this IP.

i cant ping the gateway ip for the PC.

You can't ping the router from your PC (the one you are setting this whole mess into)?

why i need bridging?
because i want to do this for my project :
http://l7-filter.sourceforge.net/L7-HOWTO-Netfilter

i want to do the bandwidth allocation base on the application layer...
so hope u know why bridging is important for me in making this project success..

after i set the bridge in my PC(linux box) , i cant ping the router anymore...

root # ping 192.168.0.1
connect: Network is unreachable

No no... that's not my question. I'm not saying that you shoudn't try bridging.

I'm trying to get you to "debug" the problem.

Let's try to clarify the situation.

You have a router. You have a PC and a laptop. Right?

I'll go on using those names:

PC side
The GW has to be the router's address.
It has to have forward enabled
It has to have masquerading activated in POSTROUTING
It MUST NOT filter the traffic comming in from the laptop.
you should be able to ping your router.
you should be able to ping the laptop.

LAPTOP side
The GW is the PCs address on the interface connected to the laptop.
you should be able to ping the pc (in the first place).
you should be able to ping the router (that depends on the PC configuration).

PS what a mess.

in my PC i try to ping the laptop and router gateway ip address...
but it come this...

root#ping 192.168.0.8
PING 192.168.0.8 56(84) bytes of data.
From 192.l168.0.17 icmp_seq=1 Destination Host Unreachable
...........
...........
.......


root#ping 192.168.0.1
PING 192.168.0.1 56(84) bytes of data.
From 192.l168.0.17 icmp_seq=1 Destination Host Unreachable
...........
...........
.......


192.168.0.1 is my GW IP,
192.168.0.8 is laptop IP address
192.168.0.17 is eth1 IP address

I see to problems there:

You have set both subnets (the one for eth0 and eth1) at the same segment.

Try using a different segment for them (don't change the one that is connected to the router ). Change the segment of the PC-LAPTOP to 192.168.1.1x

Tell me what happens when you try to ping the laptop afterwards.

the result is same...

i change eth1 to subnet 1 , ie. 192.168.1.17
then the laptop gateway set to 192.168.1.17

but still cant ping....unreachable
what is the gateway IP for eth 1? same as eth 0 gateway, is it?
what is the IP address for my laptop (using zero subnet or one subnet??) ? i tried both..but also cant...

One interface doesn't have a gateway... one interface is one interface. A HOST has one (or many) GW(s).

Your pc has a gateway and it is the router. Your laptop has a gw and it is the PC. That is enough to get to the internet.