I have an Ubuntu 16.04 system with two interfaces - eth0 configured with DHCP and eth1 configured with static ip addresses.

The /etc/network/interfaces file has the following config

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

# The Secondary network interface
auto eth1
iface eth1 inet static

## Virtual Interfaces for virtual hosts
auto eth1:11
iface eth1:11 inet static

auto eth1:12
iface eth1:12 inet static

auto eth1:13
iface eth1:13 inet static

The issue is, when DHCP server is not available on eth0 link or if the eth0 link is down, the system hangs for 5 mins, significantly slowing down the boot process.

violet@ubuntu-xenial:~$ systemd-analyze blame
      5min 241ms networking.service
          1.529s nmbd.service
          1.524s winbind.service

I tried reducing the time in /etc/systemd/system/network-online.target.wants/networking.service file which makes the system boot faster without waiting for the network service, however, that fails to load the virtual interfaces on eth1.

Is there a cleaner way to let the system boot without full network configuration on eth0 interface and still load all the static network configuration on eth1?


It seems someone was paranoid about a client not getting it's DHCP in time.

Edit this file /etc/dhcp/dhclient.conf and set timeout to a reasonable value, like

timeout 15

The default value of 300 seconds is way too high. The suggested replacement value of 15 was tested and works fine.

| improve this answer | |
  • 3
    Thank you. Labing DNS/DHCP at the moment and the 5 minute waits were killing me. – Ashley Hughes Jun 18 '17 at 7:54
  • 1
    Ubuntu has a number of odd default configs. It's been interesting... – William T Froggard Feb 22 '18 at 14:56
  • Wow, this will be really useful in further configurations. – David Tabernero M. Mar 6 '18 at 20:54
  • 2
    This does not work on Ubuntu 18, but this answer does. – xinthose Dec 3 '18 at 17:08
  • After all these years it still valid for me :) – Wajih Apr 3 '19 at 16:29

So in your /etc/network/interfaces, change this:

# The primary network interface
auto eth0
iface eth0 inet dhcp

to this:

# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp

This will start interface eth0 when the kernel detects a hotplug event from the interface (i.e. when you plug a cable in), instead of starting it at boot.

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  • 1
    This approach works well on physical hardware but it fails in virtualized environments (tried vmware and virtualbox). It looks like the virtualized kernel does not generate proper events. – dtoubelis Apr 8 '17 at 14:55
  • This approach also fixed my issues after installing a new 10G network adapter in a box that previously only had built-in 1G. Ubuntu was able to see the card and load drivers, but the boot kept stalling waiting for Raise Network Interfaces. Adjusting the device name from eth0 accordingly fixed it. – Joseph Jaramillo Sep 8 '17 at 17:15

As referenced in you can change the timeout value for raising the network interface (if running systemd):

Open a terminal window, and enter the command:

sudo nano /etc/systemd/system/network-online.target.wants/networking.service

Then change the line TimeoutStartSec=5min to a value that you choose. Save the file by pressing Ctrl+o and then Ctrl+x.

Finally, restart the daemon:

sudo systemctl daemon-reload
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  • 5
    It is generally a poor idea to start a GUI program using sudo... I have modified your answer to utilize tools which behave a bit better. – Charles Green Nov 29 '17 at 16:31
  • This is the correct answer for me. My computer is not always connected to network at boot-up. I don't want to wait 5 minutes for Ubuntu to figure that out. – Yitz Nov 25 '18 at 23:43
  • 3
    I'd love to know who the idiot is that thought a timeout of 5 minutes was a "good idea". – Clayton Dukes Dec 13 '18 at 3:56

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