Problem description: a MS Windows (7,8,8.1,10) client doesn't get an IPv6 address when it connects to the network

The client must send a DHCPv6 request with a DUID that contains the MAC address of the requesting interface. The MAC address must be registered in LANDB (Network database) in order to be allowed to get an address.

Possible workrounds:

http://marc.info/?l=linux-netdev&m=139352943109400&w=2

Hi everybody,

Today, a PowerDNS (open source dns, www.powerdns.com) deployment ran into
trouble with large amounts of IPv6 users. It appears a large telco 'flicked
the switch'. We had around 8000 DNS queries/s over IPv6, and everything
slowed to a crawl. 100% CPU utilization, most of it in the kernel. The same
amount of queries over IPv4 causes no problems.

Problem description: a CERN MS Windows device prefers IPv4 connectivity, even when IPv6 is availble and working

Solution: Remove the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters\DisabledComponents and reboot. ipv6 will be preferred when available.

Problem description:  client may not get a DHCPv6 lease for an interface even if the MAC address of the used interface is correcty registered in landb.

Solution: several clients (MacOS X, Windows, Linux) may use the MAC of any of its interfaces in the DHCPv6 request, regardless of the interface used to send it. The workaround is to register in landb all the MAC addresses in use by the client.

Problem description: an Ubuntu client doesn't configure the IPv6 address at boot time. But running manually "dhclient -6" works. dmesg reports:

[   11.997321] type=1400 audit(1372427393.005:35): apparmor="DENIED" operation="open" parent=1053 profile="/sbin/dhclient" name="/var/lib/NetworkManager/dhclient6-eth0.conf" pid=1765 comm="dhclient" requested_mask="r" denied_mask="r" fsuid=0 ouid=0

• SLC5 may have the ipv6 module disabled. Please edit the file /etc/modprobe.conf and remove the lines disabling ipv6 (#alias ipv6 off, #options ipv6 disable=1); then reboot.
• SLC6 may have the ipv6 module disabled. Please edit the file /etc/modprobe.d/ipv6.conf and remove the lines disabling ipv6 (# options ipv6 disable=1); edit the file /etc/avahi/avahi-daemon.conf and set use-ipv6=yes; then reboot.

Problem description: after growing the topology of the network, some OSPFv3 neigbhbors were stuck in the Loading phase
 
Solution: the size of the LSA update didn't fit anymore in the IPv6 MTU of the link and the router (Brocade MLXE Ironware 5.2f and 5.4c) didn't handle the case correctly. Increasing the IPv6 MTU of the link fixed the issue.
 

Problem description: a Linux client doesn't get the IPv6 client when it connects to the network

The client must send a DHCPv6 request with a DUID that contains the MAC address of the requesting interface. The MAC address must be registered in LANDB (Network database) in order to be allowed to get an address.

Possible workrounds: