dhcpcd-discuss

Testing IPv6 duplicate address detection.

A duplicate IPv6 is present on the network (say device B), configured
statically with ip address 2001::200/64.

Configure a dhcp server (saw dnsmasq), with only one IP in the range,
2001::200/64, same one that is used by device B.

Device A: running dhcpcd, in ipv6 mode.

Server/client complete the dhcpv6 transaction
(Solicit/Advertise/Request/Reply)

Client does not show any indication of IPv6 address on the interface:
# ip -6 addr
2: eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 state UP qlen
1000
    inet6 fe80::xxxxxxxxxxxxxxxxx/64 scope link
       valid_lft forever preferred_lft forever

dhcpcd syslog:
Nov 29 21:29:15 dhcpcd-6.11.5 starting
Nov 29 21:29:15 eth0: IPv6 kernel autoconf disabled
Nov 29 21:29:15 forking to background
Nov 29 21:29:15 forked to background, child pid 1478
Nov 29 21:29:15 eth0: executing `dhcpcd-run-hooks' PREINIT
Nov 29 21:29:15 eth0: executing `dhcpcd-run-hooks' CARRIER
Nov 29 21:29:15 DUID 00:01:00:01:xxxxxxxxxxxxxxxxx
Nov 29 21:29:15 eth0: IAID 54:9a:cd:3b
Nov 29 21:29:15 eth0: reading lease `/var/run/dhcpcd-eth0.lease6'
Nov 29 21:29:16 eth0: confirming prior DHCPv6 lease
Nov 29 21:29:16 eth0: delaying CONFIRM6 (xid 0x282d94), next in 0.7 seconds
Nov 29 21:29:16 eth0: broadcasting CONFIRM6 (xid 0x282d94), next in 1.0
seconds
Nov 29 21:29:16 eth0: REPLY6 received from xxxxxxxxxxxx
Nov 29 21:29:16 eth0: adding address 2001::200/128
Nov 29 21:29:16 eth0: pltime 3600 seconds, vltime 3600 seconds
Nov 29 21:29:16 eth0: renew in 1800, rebind in 3150, expire in 3600 seconds
Nov 29 21:29:16 eth0: writing lease `/var/run/dhcpcd-eth0.lease6'
Nov 29 21:29:16 eth0: waiting for DHCPv6 DAD to complete


If I attempt to configure the same address manually, things work as
expected:

# ip -6 addr
2: eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 state UP qlen
1000
    inet6 fe80::xxxxxxxxxxxxxx/64 scope link
       valid_lft forever preferred_lft forever

# ip -6 addr add 2001::200/64 dev eth0

# ip -6 addr
2: eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 state UP qlen
1000
    inet6 2001::200/64 scope global tentative dadfailed
       valid_lft forever preferred_lft forever
    inet6 fe80::xxxxxxxxxxxxxxxx/64 scope link
       valid_lft forever preferred_lft forever

Am I missing something?

Thanks
-shahid