I've set up a fresh Debian 12 system today and wanted to try out IPv6 in my network a bit.
So I set up an IPv6 ULA on my router and created a new Debian VM for testing.
The Debian VM picks up the ULA address through SLAAC just fine, but it also generates a strange and seemingly incorrect IPv6 address alongside it, one that appears to be just the EUI-64 interface identifier without any of the network prefix bits set.
The output of ip address looks like this:
inet6 ::be24:11ff:fe59:4e73/64 scope global valid_lft 2591891sec preferred_lft 604691sec inet6 fdf2:e2f0:3d5b:0:be24:11ff:fe59:4e73/64 scope global deprecated dynamic mngtmpaddr valid_lft 2591893sec preferred_lft 0sec inet6 fdf2:e2f0:3d5b:1:be24:11ff:fe59:4e73/64 scope global dynamic mngtmpaddr valid_lft 2591893sec preferred_lft 604693sec inet6 fe80::be24:11ff:fe59:4e73/64 scope link valid_lft forever preferred_lft forever Although the ULA address is generated just fine, this non-routable address :be24:11ff:fe59:4e73/64 breaks my internet access as its used as the source IP of ping or curl for example.
Output of rdisk6
Soliciting ff02::2 (ff02::2) on eth0... Hop limit : undefined ( 0x00) Stateful address conf. : Yes Stateful other conf. : No Mobile home agent : No Router preference : medium Neighbor discovery proxy : No Router lifetime : 1800 (0x00000708) seconds Reachable time : unspecified (0x00000000) Retransmit time : unspecified (0x00000000) Source link-layer address: 78:9A:18:94:4A:B4 Recursive DNS server : fdf2:e2f0:3d5b:1:be24:11ff:fe59:4e73 Recursive DNS server : fdf2:e2f0:3d5b:1:be24:11ff:feb6:90f DNS servers lifetime : 1800 (0x00000708) seconds Prefix : fdf2:e2f0:3d5b:1::/64 On-link : Yes Autonomous address conf.: Yes Valid time : 2592000 (0x00278d00) seconds Pref. time : 604800 (0x00093a80) seconds Prefix : fdf2:e2f0:3d5b::/64 On-link : Yes Autonomous address conf.: Yes Valid time : 2592000 (0x00278d00) seconds Pref. time : 0 (0x00000000) seconds from fe80::7a9a:18ff:fe94:4ab4 Router address setup:
[gateway] > /ipv6/address/print detail Flags: X - disabled, I - invalid, D - dynamic; G - global, L - link-local; S - slave; d - deprecated 1 G address=fdf2:e2f0:3d5b:1::/64 from-pool=private-pool interface= VLAN010 actual-interface=VLAN010 eui-64=no advertise=yes no-dad=no [gateway] > /ipv6/nd/print Flags: X - disabled, I - invalid; * - default 0 * interface=all ra-interval=3m20s-10m ra-delay=3s mtu=unspecified reachable-time=unspecified retransmit-interval=unspecified ra-lifetime=30m ra-preference=medium hop-limit=unspecified advertise-mac-address=yes advertise-dns=yes managed-address-configuration=yes other-configuration=no dns=fdf2:e2f0:3d5b:1:be24:11ff:fe59:4e73,fdf2:e2f0:3d5b:1:be24:11ff:feb6:90f Does anyone know why this address is being generated and how I can disable it?
::be24:11ff:fe59:4e73/64 scope globaladdress which does not have a network prefix.rdisc6 <interface>in the VM?rdisc6 -m <interface>, is that the only RA that shows up? Does the weird address re-appear after reboot? Does itsvalid_lftever reset to max every ra-interval, or does it continue counting down? And, what network software do you have running on the VM – how many SLAAC clients are there? (the kernel itself, systemd-networkd, dhcpcd, NetworkManager can all be responsible for SLAAC)rdisc6 -w 60000and lo and behold, I got a::/64RA from my LTE modem that is connected to the same network. It appears that I've never noticed it because I didn't use IPv6 in the past at all and it was off in my hosts. Thanks for getting me on the right track!