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SandPit for Wifi to eth (bridge) routing
The reason for this HOWTO: word bridge is misleadig
For a network bridge we assume a device that transfer unmodified network packets from one network connection to the other.
One can create a bridge device (virtual) and add members to it. This works only for a members of a type wired - eth network cards. Network Bridge “connects” members on level 3 of OSI model. That means communication on TCP/IP level.
When you want to add a WiFi device to the bridge, you hit to a barrier: WiFi devices communicate on a level 2 of OSI model.
So you can find many manuals on the internet, how to circumvent this (in a form of putting WiFi card to 4addr mode). This simply DO NOT WORK!
WiFi network card (member of bridge) authenticate and connects to AP, but TCP/IP packets do not travel over connection.
So searching for “wifi eth bridge” do not return a usefull solution. The culprit is word “bridge”.
General solution
A working solution is “Proxy ARP Routing” You simply enable IP forwarding and then for every device connected to eth side of a “bridge” you have to add a routing line to routing table. This can be automated.
Solution for Slackware, step-by-step
This solution is for static IP addresses. See below for A use of DHCP. Assuptions: We want to interconnect one WiFi and one eth network card - devices wlan0 and eth0
- 1. IP forwarding must be enabled at Linux kernel compilation
2. edit /etc/rc.d/rc.inet1.conf so to enable wlan0 and eth0, set them static IP numbers and set wlan0 to lowest iindex
- 3. set /etc/rc.d/rc.ip_forward
chmod +x /etc/rc.d/rc.ip_forward
4.