ipv6 temp addr generation error on debian 9.1

[Holger Zuleger]

Hi all,

I'm wondering if someone else is running into the same problem of using
temporary addresses under Debian 9.1.

I upgraded my Rasbian box to the latest Debian version
(2017-08-16-raspbian-stretch-lite.zip) which is 9.1.
$ cat /etc/debian_version
9.1

I changed the network configuration to static IPv4 and IPv6 with
autoconfiguration and the use of temporary addresses:

$ cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)

# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'

auto enxb827ebb0d7c8

iface enxb827ebb0d7c8 inet static
	<removed part>

iface enxb827ebb0d7c8 inet6 auto
	privext 2

Additionally use_tempaddr = 2 is configured in /etc/sysctl.conf for
"all" and "default".

(I know that the default for the network configuration is now to use
dhcpcd. And of course this is what I used at the very beginning.
But I saw the same problems with temporrary addresses, so I thought that
it could be a problem of dhcpcd and tried to moved it out of the network
config process.)

After a reboot, the ethernet interface have a eui-64 based permanent
ipv6 address (which was expected) but without any temporary address!
This is different to previos Linux version. However the first temporary
address is generated after the next router advertisment message comes
in, so all seems to be fine.

But after two or three days, the generation of new temporary addresses
stopps!
Now I'm stucked with two deprecated temporary addresses plus the eui64
based on on my interface.

$ ip -6 addr show label "en*" scope global | sed "s/scope global//"
2: enxb827ebb0d7c8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP
qlen 1000
   inet6 <prfx>:2126:4424:3613:8eed/64  temporary deprecated dynamic
       valid_lft 7120sec preferred_lft 0sec
   inet6 <prfx>:d5d:bc76:397d:5d6c/64  temporary deprecated dynamic
       valid_lft 7120sec preferred_lft 0sec
   inet6 <prfx>:ba27:ebff:feb0:d7c8/64  mngtmpaddr dynamic
       valid_lft 7120sec preferred_lft 3520sec

I've never seen this behavior before.
Has anyone here an idea what's going wrong with my config or with Debian
Unix? Has anyone a working config with temporary addresses on newer
Debian Linux?

Best regards
 Holger

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