I'm stumped with an occasional dropout on my bridged ethernet port.
My setup is a Pi with two ethernet (one usb ethernet) and a 3G modem (ppp). I'm using a script in /etc/ppp/if-up.d to add a route (sudo route add default dev ppp0). This seems to work fine most of the time (almost all the time). However, I've had the one usb ethernet drop out and as this will be a really remote location installation I'm somewhat nervous. I have an ip camera attached to eth1 and another pi connected to eth0. I can autossh in over ppp and get access. The main dropout did occur when I was forwarding a port from the ip camera over ppp so that I could change some settings.
I realize we shouldn't alter /etc/network/interface since Jessie but am not clear on bridging with dhcpcd.conf. So I did alter the interface and it mostly works. But I would greatly appreciate any pointers or suggestions as to how to implement the setup better. Perhaps a discerning eye could tell me my brains are full of cabbage and I'm doing it all wrong.
Here is my interface file:
# 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
#auto eth0
iface eth0 inet manual
#address 10.0.1.36
#netmask 255.255.255.0
#gateway 10.0.1.1
#allow-hotplug wlan0
#iface wlan0 inet manual
# wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
#allow-hotplug wlan1
#iface wlan1 inet manual
# wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
#auto eth1
iface eth1 inet manual
#address 10.0.1.37
#netmask 255.255.255.0
#gateway 10.0.1.1
#Bridge Setup
auto br0
iface br0 inet static
bridge_ports eth0 eth1
address 10.0.1.35
broadcast 10.0.1.255
netmask 255.255.255.0
gateway 10.0.1.1
Here is my route table before I turn on ppp:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.1.1 0.0.0.0 UG 0 0 0 br0
10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 br0
169.254.0.0 0.0.0.0 255.255.0.0 U 203 0 0 eth1
After PPP is turned on my route table looks like:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 0.0.0.0 0.0.0.0 U 0 0 0 ppp0
0.0.0.0 10.0.1.1 0.0.0.0 UG 0 0 0 br0
10.0.1.0 0.0.0.0 255.255.255.0 U 0 0 0 br0
10.64.64.64 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
169.254.0.0 0.0.0.0 255.255.0.0 U 203 0 0 eth1