[RndTbl] Implication of multiple interfaces on the same subnet?

[John Lange]

I'm just wondering if anyone has an in depth understanding of the Linux
networking stack and can tell me what the implications are for putting
two interfaces on the same network in the same subnet.

Specifically, if you have a laptop connected via both Wifi and ethernet
and both are active and have received IP addresses via DHCP, what would
the expected result of that be?

Which interface would be used for traffic to our subnet?

Here is the way the routing table looks:

Destination     Gateway         Genmask         Use Iface
192.168.5.0     0.0.0.0         255.255.255.0   eth0
192.168.5.0     0.0.0.0         255.255.255.0   wlan0
127.0.0.0       0.0.0.0         255.0.0.0       lo
0.0.0.0         192.168.5.254   0.0.0.0         eth0

The routing table indicates that eth0 is preferred for traffic outside
my network but how was that determination made?

If I unplug the ethernet cable it immediately changes the routing table
so that the wlan0 interface is the default gateway.

I'm wondering what controls that behaviour?

-- 
John Lange
www.johnlange.ca