Why is the network configuration I set in /etc/network/interfaces ignored on Ubuntu 17.10?

Question

I've just installed ubuntu server 17.10. During installation, it suggested me to connect to the network through wifi, and so i did. After installation was finished and system was rebooted, computer connected to the wifi automatically (which means, it saved the connection creds somewhere). But in /etc/network/interfaces i found nothing. I need my computer connect to wifi network with static ip, so I've put configuration into the /etc/network/interfaces:

# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# Generated by debian-installer.

# The loopback interface
auto lo
iface lo inet loopback


iface wlp2s0b1 inet static
        wpa-driver wext
        address 192.168.0.12
        netmask 255.255.255.0
        gateway 192.168.0.1
        wpa-ssid *****
        wpa-psk **********
        dns-nameservers 8.8.8.8 192.168.0.1
auto wlp2s0b1

When system starts, it doesn't connect using my configuration. It does only after

sudo ifdown wlp2s0b1 && sudo ifup -v wlp2s0b1

and after this command, system getting a SECOND IP! Server is still available by the ip it gets from DHCP, and in the same time, it is available by the static ip!

Solution 1

Networking is handled by netplan by default in Ubuntu Server 17.10 and later. I suggest that you edit the /etc/netplan/01-netcfg.yaml file to read:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  wifis:
    wlp2s0b1:
      dhcp4: no
      dhcp6: no
      addresses: [192.168.0.21/24]
      gateway4: 192.168.0.1
      nameservers:
        addresses: [8.8.8.8,192.168.0.1]
      access-points: 
        "******":
          password: "**********"

Exit and save your changes by running the command:

sudo netplan generate
sudo netplan apply

Please note and follow the spacing and indentation. Also note that the SSID and password are in between quotes ".

Comment out all the wlp2s0b1 stanzas in /etc/network/interfaces and reboot.

Any improvement?

NOTE: The exact method to set a static IP address for a server with netplan and wifi is hard to find. We may need to tweak the settings a bit.

Solution 2

I suggest you to completely remove netplan package and use networkd by creating config(s) in /etc/systemd/network/ directory. Netplan exists only in Ubuntu and there are no one in any other distros.

Comments

[chili555]

Please edit your question to add the result of: cat /etc/network/interfaces . Welcome to Ask Ubuntu.

[lucius]

> Please edit your question to add the result of: cat /etc/network/interfaces. Done! > Welcome to Ask Ubuntu. Thank you!

[chili555]

Please edit out this: wpa-driver wext Next, do: sudo ifdown wlp2s0b1 && sudo ifup -v wlp2s0b1 The -v for verbose should produce some clues as to what's going on or going wrong. Paste it here and give us the link: paste.ubuntu.com

[lucius]

Should i remove this line? wpa-driver wext

[chili555]

Yes, please and then: sudo ifdown wlp2s0b1 && sudo ifup -v wlp2s0b1 and then paste the output so we can see what's going wrong. Also, when it gets an IP address, presumably by DHCP, what is the address?

[lucius]

paste.ubuntu.com/25963423 As i described in the topic, this command made server to get a second ip. Now server is reachable by static ip 192.169.0.12 and by the ip, which it has from DHCP. The address from DHCP is 192.168.0.21 (it's in range from 192.168.0.20-255 configured on router)

[chili555]

"RTNETLINK answers: Cannot assign requested address" Does some other device on the network have the address? Are you quite sure that the DHCP range is from x.20 to x.255 (actually, it is likely 254 and 255 are reserved.) Do you really expect 200+ guests that need DHCP? Have you tried rebooting the server and the router?

[lucius]

IPs are in use: 192.168.0.21 (server), 192.168.0.26, 192.168.0.22, 192.168.0.24, 192.168.0.23, 192.168.0.20. About range: yes, it was below 254, sorry. I've changed the top restriction to 192.168.0.35. I was rebooting server tens times. Now i rebooted my router and then server. Nothing change.

[chili555]

May we see: ps aux | grep -i -e network -e wicd

[lucius]

Sure! paste.ubuntu.com/25963659

[chili555]

!!! May we see: ls /etc/netplan? Possible clue: wiki.ubuntu.com/Netplan

[lucius]

YES!!! It is there! What should i do? Just remove the wifis config from the file or entire file?

[chili555]

No, I suggest that we properly configure it and abandon /etc/network/interfaces. I'm reading and will propose an answer in a while. Please paste its name and contents.

[lucius]

name: 01-netcfg.yaml; content: paste.ubuntu.com/25963779

[lucius]

You spent 2 hours (!) of your life on my problem, and now it is solved! Thank you! I love ubuntu community!

[chili555]

No, thank you! I enjoy challenging problems. Glad it's working.

[Alexey Ce]

netplan is just for server network admin?

[chili555]

@Thufir netplan is also used in destop installations but, by default, turns over configuration to Network Manager.

[Nabheet]

This is awesome! However, I needed to install wpasupplicant on my ubuntu server too.

[chili555]

@Fabby I believe quotes are " and double-quotes are "" which is incorrect.

[Fabby]

Oh, I thought single quotes were ' and double quotes were ". Removing... Sorry for having caused you grief! ;-)

[kol]

sudo netplan generate should be run before sudo netplan apply, see askubuntu.com/a/883378/164374

[kol]

You also need to have wpasupplicant installed, or networkctl will say no-carrier.

[karel]

The netplan.io package does not exist in the default 17.10 repositories.

[Gannet]

Sorry, it is in 18.04. If you want to move to networkd, you just neet to: 1) sudo systemctl enable systemd-networkd 2) sudo rm /etc/network/interfaces 3) sudo rm /etc/netplan/*