Ethernet Wifi failover

[Olivier Cochard-Labbé]

 Hi,

here is an old post from my blog that can useful on the documentation.

I want a simple behavior with my laptop:

   1. If Ethernet cable connected use this connectivity, otherwise use the
   wireless;
   2. I want to kept the same IP addresses, event if I'm using DHCP client.

The solution is quiet simple:

   1. set-up an aggregate interface in failover mode with Ethernet as
   primary and wireless as backup;
   2. Put the Ethernet NIC MAC address on the wireless NIC.

Here are how to do it:

# *ifconfig -l*
iwn0 bge0 lo0
=> My Ethernet NIC is "bge0" and wireless is "iwn0" here

# *set MAC=`ifconfig bge0 | grep ether | cut -d ' ' -f 2`*
# *sysrc ifconfig_bge0=up*
ifconfig_bge0:  -> up
# *sysrc wlans_iwn0=wlan0*
wlans_iwn0:  -> wlan0
# *sysrc ifconfig_iwn0="ether $MAC"*
ifconfig_iwn0:  -> ether 00:1c:23:25:ab:45
# *sysrc ifconfig_wlan0="WPA up"*
ifconfig_wlan0: WPA DHCP -> WPA up
# *sysrc cloned_interfaces=lagg0*
cloned_interfaces:  -> lagg0
# *sysrc ifconfig_lagg0="laggproto failover laggport bge0 laggport wlan0
DHCP"*
ifconfig_lagg0:  -> laggproto failover laggport bge0 laggport wlan0 DHCP
# *sysrc ifconfig_lagg0_ipv6="inet6 accept_rtadv"*
ifconfig_lagg0_ipv6:  -> inet6 accept_rtadv
# *service netif restart*

And now with Ethernet cable unplugged:

# *ifconfig lagg0*
lagg0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
    ether 00:1c:23:25:ab:45
    inet6 fe80::41d:23ff:fe25:ab78%lagg0 prefixlen 64 scopeid 0x4
    inet6 2a01:e35:9b9d:a1a0:41d:23ff:fe25:ab45 prefixlen 64 autoconf
    inet 192.168.100.7 netmask 0xffffff00 broadcast 192.168.100.255
    nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
    media: Ethernet autoselect
    status: active
    laggproto failover lagghash l2,l3,l4
    laggport: wlan0 flags=4<ACTIVE>
    laggport: bge0 flags=1<MASTER>


Then If I plug the Ethernet cable:


# ifconfig lagg0
lagg0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
    ether 00:1c:23:25:ab:45
    inet6 fe80::41d:23ff:fe25:ab45%lagg0 prefixlen 64 scopeid 0x4
    inet6 2a01:e35:9b9d:a1a0:41d:23ff:fe25:ab45 prefixlen 64 autoconf
    inet 192.168.100.7 netmask 0xffffff00 broadcast 192.168.100.255
    nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
    media: Ethernet autoselect
    status: active
    laggproto failover lagghash l2,l3,l4
    laggport: wlan0 flags=0<>
    laggport: bge0 flags=5<MASTER,ACTIVE>