I am testing a GSM dongle as a reserve network if internet fails. The problem is that when i plug in the dongle, two default gateways are added to the routing table.
This is the config file with high metric cost for the gsm network:
# interfaces(5) file used by ifup(8) and ifdown(8)
# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto lo
iface lo inet loopback
iface eth0 inet manual
allow-hotplug wlan0
iface wlan0 inet manual
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface wlan0 inet dhcp
# GSM 3G Hi_Link USB modem
allow-hotplug eth1
iface eth1 inet dhcp
metric 1000
this is the routing table without dongle
pi@emonpi(ro):~$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default Broadcom.Home 0.0.0.0 UG 202 0 0 eth0
192.168.3.0 * 255.255.255.0 U 202 0 0 eth0
this is with dongle
pi@emonpi(ro):~$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default Broadcom.Home 0.0.0.0 UG 202 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 204 0 0 eth1
default 192.168.1.1 0.0.0.0 UG 1000 0 0 eth1
192.168.1.0 * 255.255.255.0 U 204 0 0 eth1
192.168.3.0 * 255.255.255.0 U 202 0 0 eth0
please comment
Hax