[Bridge] Problems with Bridging 3 pc's network

[Bridge] Problems with Bridging 3 pc's network

[Filippo Graziola]

Hi sir,
I'm a student of Trento University and I'm working on
a network
project. I need to create a network like this:

PC.1>--ethernet cable-->MAIN_PC(ubuntu
linux)>------wireless----->PC.2

PC.1 ip: 192.168.0.1
MAIN_PC ip: 192.168.0.2
PC.2 ip: 192.168.0.3
netmask 255.255.255.0

I followed the instruction of the HOWTO and I made a
bridge on MAIN_PC.
Previously I set the wireless interface (eth0 - intel
2200B/G) with
ad-hoc mode and I gave it a essid and a channel.
Without the bridge I can
ping from MAIN_PC all the others but I noticed that
when the bridge is
up I can't ping from the PC.2 the PC.1 (problem nr°1)
and I can ping
from PC.2 the MAIN_PC only for a short start time
(problem nr°2).

When I give this command as root:

echo "1" > /proc/sys/net/ipv4/ip_forward

this is the answer:

bash: /proc/sys/net/ipv4/ip_forward: Permission denied

Maybe I think this is the reason because I get problem
nr°1, is it
true?
What should I do?

I have no idea for the second problem.
Can you please help.
Sorry for my english, I hope that my explanation were
enough clear
Thanks a lot

Filippo Graziola


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Re: [Bridge] Problems with Bridging 3 pc's network

[Alex Zeffertt]

Filippo Graziola wrote:
> Hi sir,
> I'm a student of Trento University and I'm working on
> a network
> project. I need to create a network like this:
> 
> PC.1>--ethernet cable-->MAIN_PC(ubuntu
> linux)>------wireless----->PC.2
> 
> PC.1 ip: 192.168.0.1
> MAIN_PC ip: 192.168.0.2
> PC.2 ip: 192.168.0.3
> netmask 255.255.255.0
> 
> I followed the instruction of the HOWTO and I made a
> bridge on MAIN_PC.
> Previously I set the wireless interface (eth0 - intel
> 2200B/G) with
> ad-hoc mode and I gave it a essid and a channel.
> Without the bridge I can
> ping from MAIN_PC all the others but I noticed that
> when the bridge is
> up I can't ping from the PC.2 the PC.1 (problem nr°1)
> and I can ping
> from PC.2 the MAIN_PC only for a short start time
> (problem nr°2).
> 
> When I give this command as root:
> 
> echo "1" > /proc/sys/net/ipv4/ip_forward
> 
> this is the answer:
> 
> bash: /proc/sys/net/ipv4/ip_forward: Permission denied
> 

This is not the cause of your problem.  You are trying to
bridge ethernet packets at layer 2, not route IP packets
at layer 3.


> Maybe I think this is the reason because I get problem
> nr°1, is it
> true?
> What should I do?
> 

  * Do a "brctl show" and send the results to the list.

  * Do an "ifconfig -a" and send the results to the list.

You may have an IP address problem.  After you have added interfaces
(e.g. eth0 and wlan0) to a bridge (br0) you must remove the IP addresses
from the interfaces with, for example,  "ifconfig eth0 0.0.0.0 up" and "ifconfig
wlan 0.0.0.0 up", and then apply the IP address to br0, e.g. "ifconfig
br0 192.168.0.2 up"

Alex


> I have no idea for the second problem.
> Can you please help.
> Sorry for my english, I hope that my explanation were
> enough clear
> Thanks a lot
> 
> Filippo Graziola
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Poco spazio e tanto spam? Yahoo! Mail ti protegge dallo spam e ti da tanto spazio gratuito per i tuoi file e i messaggi 
> http://mail.yahoo.it 
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Re: [Bridge] Problems with Bridging 3 pc's network

[Stephen Hemminger]

Filippo Graziola wrote:
> Hi sir,
> I'm a student of Trento University and I'm working on
> a network
> project. I need to create a network like this:
>
> PC.1>--ethernet cable-->MAIN_PC(ubuntu
> linux)>------wireless----->PC.2
>
> PC.1 ip: 192.168.0.1
> MAIN_PC ip: 192.168.0.2
> PC.2 ip: 192.168.0.3
> netmask 255.255.255.0
>
> I followed the instruction of the HOWTO and I made a
> bridge on MAIN_PC.
> Previously I set the wireless interface (eth0 - intel
> 2200B/G) with
> ad-hoc mode and I gave it a essid and a channel.
> Without the bridge I can
> ping from MAIN_PC all the others but I noticed that
> when the bridge is
> up I can't ping from the PC.2 the PC.1 (problem nr°1)
> and I can ping
> from PC.2 the MAIN_PC only for a short start time
> (problem nr°2).
>
> When I give this command as root:
>
> echo "1" > /proc/sys/net/ipv4/ip_forward
>   
1. You are Bridging (layer 2) not Routing (layer 3). 

2. Bridging ethernet to wireless doesn't work in most cases because wireless
    bridging requires NDS support which is not in the bridge code, and 
would also
    require different wireless device drivers (using softmac).

See the FAQ on http://linux-net.osdl.org/index.php/Bridge