Gfilui

I'm running Ubuntu Server 16.04.4

After a lot of struggling I managed to configure both ethernet and wireless connections.

The content of /etc/network/interfaces file is this:

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# Ethernet network interface
allow-hotplug enp9s0
iface enp9s0 inet static
 address 192.168.1.150
 netmask 255.255.255.0
 gateway 192.168.1.1

# Wireless network interface
allow-hotplug wlp5s0b1
iface wlp5s0b1 inet static
 address 192.168.1.151
 netmask 255.255.255.0
 gateway 192.168.1.1
 dns-nameservers 192.168.1.1
 wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

up route add default gw 192.168.1.1 dev wlp5s0b1

and in /etc/wpa_supplicant/wpa_supplicant.conf there is the output of:

wpa_passphrase "MY SSID" MY_PASSWORD | sudo tee /etc/wpa_supplicant/wpa_supplicant.conf

which is:

network=
 ssid="MY SSID"
 #psk="MY_PASSWORD_IN_CLEAR"
 psk=LONG_HEX_STRING

Now, ifconfig shows that:

enp9s0 Link encap:Ethernet IndirizzoHW 00:24:54:ad:ac:b4 
 indirizzo inet:192.168.1.150 Bcast:192.168.1.255 Maschera:255.255.255.0
 indirizzo inet6: fe80::224:54ff:fead:acb4/64 Scope:Link
 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
 RX packets:435 errors:0 dropped:0 overruns:0 frame:0
 TX packets:195 errors:0 dropped:0 overruns:0 carrier:0
 collisioni:0 txqueuelen:1000 
 Byte RX:54426 (54.4 KB) Byte TX:26620 (26.6 KB)
 Interrupt:18 

lo Link encap:Loopback locale 
 indirizzo inet:127.0.0.1 Maschera:255.0.0.0
 indirizzo inet6: ::1/128 Scope:Host
 UP LOOPBACK RUNNING MTU:65536 Metric:1
 RX packets:14256 errors:0 dropped:0 overruns:0 frame:0
 TX packets:14256 errors:0 dropped:0 overruns:0 carrier:0
 collisioni:0 txqueuelen:1 
 Byte RX:1055216 (1.0 MB) Byte TX:1055216 (1.0 MB)

wlp5s0b1 Link encap:Ethernet IndirizzoHW 00:1b:b1:48:12:86 
 indirizzo inet:192.168.1.151 Bcast:192.168.1.255 Maschera:255.255.255.0
 indirizzo inet6: fe80::21b:b1ff:fe48:1286/64 Scope:Link
 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
 RX packets:695 errors:0 dropped:0 overruns:0 frame:0
 TX packets:30 errors:0 dropped:0 overruns:0 carrier:0
 collisioni:0 txqueuelen:1000 
 Byte RX:125974 (125.9 KB) Byte TX:3316 (3.3 KB)

and the routing table is this:

tommy@ubuntu-server:~$ route -n
Tabella di routing IP del kernel
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 enp9s0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 enp9s0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 wlp5s0b1

If I ping with the ethernet cable connected, all works good.

But if I remove the ethernet cable and ping 8.8.8.8 it's not working.

Now my guess is that in the routing table is missing a line like this:

0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 wlp5s0b1

In fact, if I run:

sudo route add default gw 192.168.1.1 wlp5s0b1

then the routing table is:

tommy@ubuntu-server:~$ route -n
Tabella di routing IP del kernel
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 wlp5s0b1
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 enp9s0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 enp9s0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 wlp5s0b1

and ping 8.8.8.8 without the ethernet cable work just fine.

So my question is this: is there a way of keep permanent the route that I added?

I've already tried to write the command in the last line of the /etc/network/interfaces file, as you can see above, in many different ways:

• up route add default gw 192.168.1.1


• up route add default gw 192.168.1.1 wlp5s0b1


• up route add default gw 192.168.1.1 dev wlp5s0b1


• as above but with up ip route ...


• as above but with post-up instead of up

but it's not working.

Am I missing the correct syntax or is there any other solution?

Thanks for your help!