Comment 31 for bug 1551351

I did a fresh install of artful on a shuttle SZ170 with the following ethernet adapters according to `lshw`:

          *-network
                description: Ethernet interface
                product: I211 Gigabit Network Connection
                vendor: Intel Corporation
                physical id: 0
                bus info: pci@0000:03:00.0
                logical name: enp3s0
                version: 03
                serial: 80:ee:73:c8:ec:1a
                size: 1Gbit/s
                capacity: 1Gbit/s
                width: 32 bits
                clock: 33MHz
                capabilities: pm msi msix pciexpress bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
                configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.4.0-k duplex=full firmware=0. 6-1 ip=192.168.0.14 latency=0 link=yes multicast=yes port=twisted

and

        *-network
             description: Ethernet interface
             product: Ethernet Connection (2) I219-LM
             vendor: Intel Corporation
             physical id: 1f.6
             bus info: pci@0000:00:1f.6
             logical name: enp0s31f6
             version: 31
             serial: 80:ee:73:c8:ec:1b
             size: 1Gbit/s
             capacity: 1Gbit/s
             width: 32 bits
             clock: 33MHz
             capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
             configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k duplex=full firmware=0.8-4 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
             resources: irq:126 memory:df200000-df21ffff

I have dhclient and bind9 installed:

root@atlantis:~# dhclient --version
isc-dhclient-4.3.5
root@atlantis:~# dpkg --list|grep -i dhc
ii dnsmasq-base 2.78-1 amd64 Small caching DNS proxy and DHCP/TFTP server
ii isc-dhcp-client 4.3.5-3ubuntu2 amd64 DHCP client for automatically obtaining an IP address
ii isc-dhcp-common 4.3.5-3ubuntu2 amd64 common manpages relevant to all of the isc-dhcp packages
root@atlantis:~# dpkg --list|grep -i bind9
ii bind9-host 1:9.10.3.dfsg.P4-12.6ubuntu1 amd64 Version of 'host' bundled with BIND 9.X
ii libbind9-140:amd64 1:9.10.3.dfsg.P4-12.6ubuntu1 amd64 BIND9 Shared Library used by BIND

I've disabled the second ethernet adapter. Periodically `enp3s0` looses its IP address which it got via dhcp from my cable router. I think its related to this bug. I understand the basics of dhcp (I can run some commands), so I don't know the next steps to continue the diagnosis.