Yrurtj

I have been using bridge utils previously to connect my network connected computers to a single interface on my Linux computer. The problem I'm having is when I installed a new Linux (with Slackware) the two connected computers cannot even ping each other. Basically the computers are connected as:

client - server - client

           |

       [Internet]

So I am trying to get the two clients to connect to each other. Both can access the Internet, firewalls are shut off at both clients when testing.

Internet is on eth0, and I have one bridge set up as

bridge name     interfaces

br0             eth1, eth2

ip addr br0 and ip route show shows respectively

inet 10.0.0.1/24 brd 10.0.0.255

10.0.0.0/24 dev br0  proto kernel  scope link  src 10.0.0.1

So it seems to me like a call from my client should be routed directly to my br0 interface, which should get it right.

How do I configure my Slackware distro to route two network cable attached computers to be able to see eachother, preferably using bridge utils?

Is the firewall on the server disabled? It maybe that there are some firewall rules that are blocking the packets. Look at the output of iptables (must be run as root) and if you see anything other than ACCEPT rules/policies then they may be blocking things.

iptables -L

and

iptables -t nat -L

If the two devices cannot ping each other it sounds like the bridge is not correctly setup. There is no ip protocol routing involved in the bridge. What is the output of brctl show ? That should show something like

$ brctl show

bridge name     bridge id               STP enabled     interfaces

br0             8000.003018a46079       no              eth1

                                                        eth2

If both interfaces are not listed there then that needs correcting.

You may also like to try the brctl showmacs br0 command and if STP (spanning tree protocol) was enabled above the brctl showstp br0 command. The former should show the mac addresses of the two devices and the for the latter you should look to make sure that each port is in state forwarding

Given that you say that each can access the internet I assume that all of the interfaces have been brought up. If not the following should do that.

ip link set br0 up

ip link set eth0 up

ip link set eth1 up

ip link set eth2 up

Check if ip fowarding is enabled on the server with the command

sysctl net.ipv4.ip_forward

if this gives 0, do

sysctl -w net.ipv4.ip_forward=1

as root on the server. If this helps, make the change permanent by editing /etc/sysctl.conf