/etc/network/interfaces and IPv6

[Rainer Dorsch]

Hello,

I am just wondering why ipv6 gets configured for enp1s0, even though I do not
request that in /etc/network/interfaces (?).

I suspect NetworkManager takes care of that, but I always thought, network
manager does not touch interfaces mentioned in /etc/network/interface?

System is stretch.

[ 17.057438] r8169 0000:01:00.0 enp1s0: link down
[ 17.057440] r8169 0000:01:00.0 enp1s0: link down
[ 17.057546] IPv6: ADDRCONF(NETDEV_UP): enp1s0: link is not ready
[ 28.782440] r8169 0000:01:00.0 enp1s0: link up
[ 28.782473] IPv6: ADDRCONF(NETDEV_CHANGE): enp1s0: link becomes ready


***@gigabyte:~# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto enp1s0
allow-hotplug enp1s0
iface enp1s0 inet dhcp
#iface eno1.7 inet6 auto
***@gigabyte:~# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP
group default qlen 1000
link/ether 74:d4:35:7b:0d:d8 brd ff:ff:ff:ff:ff:ff
inet 192.168.7.201/24 brd 192.168.7.255 scope global enp1s0
valid_lft forever preferred_lft forever
inet6 2a02:8070:898f:e4fc:76d4:35ff:fe7b:dd8/64 scope global mngtmpaddr
dynamic
valid_lft 14307sec preferred_lft 14307sec
inet6 fe80::76d4:35ff:fe7b:dd8/64 scope link
valid_lft forever preferred_lft forever
***@gigabyte:~#

Many thanks
Rainer

[Reco]

Hi.

Post by Rainer Dorsch
Hello,
I am just wondering why ipv6 gets configured for enp1s0, even though I do not
request that in /etc/network/interfaces (?).

<skip>

Post by Rainer Dorsch
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP
group default qlen 1000
link/ether 74:d4:35:7b:0d:d8 brd ff:ff:ff:ff:ff:ff
inet6 2a02:8070:898f:e4fc:76d4:35ff:fe7b:dd8/64 scope global mngtmpaddr dynamic
valid_lft 14307sec preferred_lft 14307sec

You've got your IPv6 address via Router Advertisement (mngtmpaddr
dynamic, limited address lifetime).
And you don't need anything but a Linux kernel to get it.

If you don't need IPv6 on that interface for some reason - add the
following to your /etc/network/interfaces:

iface enp1s0 inet6 auto
accept_ra 0

Reco

[Rainer Dorsch]

Hi Reco,

many thanks, your answer worked well.

Rainer

Post by Reco
Hi.

Post by Rainer Dorsch
Hello,
I am just wondering why ipv6 gets configured for enp1s0, even though I do
not request that in /etc/network/interfaces (?).

<skip>

Post by Rainer Dorsch
2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UP group default qlen 1000
link/ether 74:d4:35:7b:0d:d8 brd ff:ff:ff:ff:ff:ff
inet6 2a02:8070:898f:e4fc:76d4:35ff:fe7b:dd8/64 scope global
mngtmpaddr dynamic>
valid_lft 14307sec preferred_lft 14307sec

You've got your IPv6 address via Router Advertisement (mngtmpaddr
dynamic, limited address lifetime).
And you don't need anything but a Linux kernel to get it.
If you don't need IPv6 on that interface for some reason - add the
iface enp1s0 inet6 auto
accept_ra 0
Reco