Debian – Fix Vlan Interface Not Coming Up

debiannetworking

I have a vlan configured for my network interface. Since last reboot this does not come up anymore and if I try to start it manually, it fails

sudo ifup eno1.4000
RTNETLINK answers: File exists
ifup: failed to bring up eno1
ifup: could not bring up parent interface eno1

My os is debian 10 and this is my config:

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback
iface lo inet6 loopback

auto eno1
iface eno1 inet static
  address xxx.xxx.xxx.xxx
  netmask 255.255.255.224
  gateway xxx.xxx.xxx.xxx
  up route add -net xxx.xxx.xxx netmask 255.255.255.224 gw xxx.xxx.xxx.xxx dev eno1

iface eno1 inet6 static
  address xxxx:xxxx:xxxx:xxxx::x
  netmask 64
  gateway fe80::1

auto eno1.4000
iface eno1.4000 inet static
  address 192.168.100.4
  netmask 255.255.255.0
  vlan-raw-device eno1
  mtu 1400a

bootlog shows

Aug 19 17:08:50 xxxx ifup[820]: ifup: failed to bring up eno1
Aug 19 17:08:50 xxxx ifup[820]: RTNETLINK answers: File exists
Aug 19 17:08:50 xxxx ifup[820]: ifup: failed to bring up eno1
Aug 19 17:08:50 xxxx ifup[820]: ifup: could not bring up parent interface eno1

Best Answer

ifup: could not bring up parent interface eno1 suggests that there is some error when bringing up eno1. I suppose it's because your up command fails, so you could try using post-up instead or remove it, then run that command manually to check for possible issues.

By the way, you don't need to use vlan-raw-device, here is a note from Debian network configuration reference:

Note: If you name your VLAN interfaces ethX.YYY, then there is no need to specify the vlan-raw-device, as the raw device can be retrieved from the interface name.

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