I configured br0 (My bridge)



[root@localhost ~]# ifconfig eth0 0.0.0.0 up
[root@localhost ~]# ifconfig eth1 0.0.0.0 up
[root@localhost ~]# brctl addbr br0
[root@localhost ~]# brctl addif br0 eth0
[root@localhost ~]# brctl addif br0 eth1
[root@localhost ~]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.0050ba1e9288 no eth0
eth1
[root@localhost ~]# brctl showstp br0
br0
STP is disabled for this interface

[root@localhost ~]# brctl stp br0 on
[root@localhost ~]# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.0050ba1e9288 yes eth0
eth1
[root@localhost ~]# brctl showstp br0
br0
bridge id 8000.0050ba1e9288
designated root 8000.0050ba1e9288
root port 0 path cost 0
max age 19.99 bridge max age 200.00
hello time 1.99 bridge hello time 20.00
forward delay 150.00 bridge forward delay 14.99
ageing time 299.95 gc interval 0.00
hello timer 0.00 tcn timer 0.00
topology change timer 0.00 gc timer 0.00
flags


eth0 (1)
port id 8001 state disabled designated root 8000.0050ba1e9288 path cost 19
designated bridge 8000.0050ba1e9288 message age timer 0.00
designated port 8001 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags

eth1 (2)
port id 8002 state disabled designated root 8000.0050ba1e9288 path cost 100
designated bridge 8000.0050ba1e9288 message age timer 0.00
designated port 8002 forward delay timer 0.00
designated cost 0 hold timer 0.00
flags


I gave a IP to BR0

ifconfig br0 xxx.xxx.xxx.165 netmask 255.255.255.0 up



The Br0 was first set in both eth ip 0.0.0.0 and the network was contected to the hub when I started the br0 configuration. so PC1 could have internet.

After all that, I took the network cable from the hub and put directly to the BR0.

I can ping a ip from the network, and the PC1, and PC1 can ping also.
But cant ping any website, neither have internet or FTP.

Its also wierd, because, when I take the cable off the PC1 and put on again, it will lose ip, and wont get it never again... and wont ping the network.



ht p://img157.echo.cx/img157/9228/br06ik.jpg


Why cant I get a ip when I have the br0 betwen the network and hub... why could I first ping and didnt had internet??


Many thanks for your help!

Hi,
I had a very similar problem with setting up bridging (brctl) in Linux. Basically, only ICMP pings could go across the bridge, and even traceroutes (icmp+udp) with no DNS (traceoute -n) would work, but DNS queries, dhcp, http, ftp and other protocols simply were not working at all.

After hours of looking into this, it turns out that "iptables" (a firewall) was running in the background without me knowing. After I removed all the firewall rules, the bridge started working as expected, and all IP protocols were now traversing the bridge correctly.

To check if this is what is happening with you do:
iptables --list (lists firewall rules)
iptables --flush (deletes ALL the firewall rules)

NOTE: Do NOT just delete all the firewall rules, especially if you are working in a production environment. In my case, it was an isolated lab scenario with only 3 computers, so I knew there would be no consequences.

Depending what version of linux you are running there may be older or different versions of firewalls running (going by different names, i.e. ipchains instead of iptables). Be sure to check what firewalls other than iptables might exist for your particular version of linux.

Best wishes,
Adeptus