Mint changes default route when eth0 comes back and breaks existing tcp connections

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http://unix.stackexchange.com – I have two interfaces on my laptop (eth0, wlan0). lets say I am moving away from desk and connecting to an internal network A using openvpn software which uses wlan0 as gateway. I then ssh to a few vms inside this network A. when I return back to my desk, the system detects eth0 is available and automatically changes default route. I then lose vpn connection and all the ssh sessions with the vms in network A. on wlan0 Destination Gateway Genmask Flags Metric Ref Use Iface UG 0 0 0 wlan0 when reestablished (HowTos)