Category: Knowledge Base

  • MS Windows client doesn’t get IPv6 address from DHCPv6

    MS Windows client doesn’t get IPv6 address from DHCPv6 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…

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  • ISC DHCPv6 configuration excerpt

    ISC DHCP 4.3.1

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  • Linux IPv6 routing table max_size badly dimensioned compared to IPv4

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  • Knowledge Base articles also availables in Service Now

    IPv6 Knowledge base articles are also available in Service Now Knowledge Base

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  • CERN MS Windows device prefers IPv4 over IPv6

    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.

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  • Testing IPv6 connectivity

    Here is a list of of web sites to test IPv6 connectivity:

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  • Using DHCPv6 with SLC6

    This page is obsolete and may no longer be relevant with the latest version of SLC6. Problem description: using DHCPv6 with old version of SLC6 at CERN requires some tweaking of the network configuration files, due to s RedHat bug (https://bugzilla.redhat.com/show_bug.cgi?id=591630, https://bugzilla.redhat.com/show_bug.cgi?id=634857) and the way devices are authorized to connect to the network at CERN…

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  • Client may not get a DHCPv6 lease even if registered

    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…

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  • Ubuntu 13.04 client doesn’t get IPv6 address at boot time

    Ubuntu 13.04 client doesn’t get IPv6 address at boot time 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 Solution: there’s a typo in the /etc/apparmor.d/sbin.dhclient file. In…

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  • SLC5 and SLC6 may have IPv6 disabled

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