LinuxQuestions.org - Ubuntu on Arm - Network Partially Dropping Out

I have a few linux machines in my house and I recently purchased a Orange Pi Plus 2E which is like a Raspberry Pi. It's arm-based and I installed a version of Ubuntu on it that is compatible with arm (16.04 Xenial). Anyway, I'm having a problem with it that I don't yet know how to solve.

I haven't messed with any of the networking files yet, all the linux machines in my house use DHCP. When I power the system up and everything is fresh, the routes look good:

Code:

> ip route

default via 192.168.0.1 dev eth0

default via 192.168.0.1 dev eth0  proto static  metric 100

169.254.0.0/16 dev eth0  scope link  metric 1000

192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.5  metric 100

>

When I got home from work, the last route disappears and I'm unable to get to the machine with my other computers on the network. If I manually add the route using a command like this:

Code:

/sbin/ip route add 192.168.0.0/24 dev eth0

it works again, but why is this happening? I've found a clue in the syslog, it seems to be happening when the dhclient service needs to renew its IP address:

Code:

Apr 26 07:18:41 localhost dhclient[856]: DHCPREQUEST of 192.168.0.5 on eth0 to 192.168.0.1 port 67 (xid=0x79d200c8)

Apr 26 07:18:41 localhost dhclient[856]: DHCPACK of 192.168.0.5 from 192.168.0.1

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0208]  address 192.168.0.5

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0214]  plen 24 (255.255.255.0)

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0216]  gateway 192.168.0.1

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0217]  server identifier 192.168.0.1

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0218]  lease time 86400

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0219]  nameserver '192.168.0.1'

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0220]  domain name 'mynet'

Apr 26 07:18:42 localhost NetworkManager[475]: <info>  [1524748722.0222] dhcp4 (eth0): state changed bound -> bound

Apr 26 07:18:42 localhost NetworkManager[475]: <error> [1524748722.0280] platform-linux: do-add-ip4-address[2: 192.168.0.5/24]: failure 17 (File exists)

Apr 26 07:18:42 localhost NetworkManager[475]: <error> [1524748722.0301] platform-linux: do-add-ip4-route[2: 0.0.0.0/0 100]: failure 3 (No such process)

Apr 26 07:18:42 localhost NetworkManager[475]: <warn>  [1524748722.0302] default-route: failed to add default route 0.0.0.0/0 via 192.168.0.1 dev 2 metric 100 mss 0 src user with effective metric 100

Apr 26 07:18:42 localhost dbus[448]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'

Apr 26 07:18:42 localhost dhclient[856]: bound to 192.168.0.5 -- renewal in 32998 seconds.

Apr 26 07:18:42 localhost systemd[1]: Starting Network Manager Script Dispatcher Service...

Apr 26 07:18:42 localhost dbus[448]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'

Apr 26 07:18:42 localhost systemd[1]: Started Network Manager Script Dispatcher Service.

Apr 26 07:18:42 localhost nm-dispatcher: req:1 'dhcp4-change' [eth0]: new request (1 scripts)

Apr 26 07:18:42 localhost nm-dispatcher: req:1 'dhcp4-change' [eth0]: start running ordered scripts...

The NetworkManager cannot set the route (file exists). I've googled around looking for the error messages and I've come up empty handed. Does anyone know how I can permanently solve this issue? My other linux machines work like clockwork but this one is having a little difficulty and I can't figure out what is different between the installations.

Thanks,
-Greg