Need help with ULA addressing scheme



  • Hi, I'm trying to build an IPv6 ULA environment, but I'm having issues in understanding some of the basics.

    I used https://cd34.com/rfc4193/ to generate a IPv6 address on my LAN interface. I assigned LAN the following v6 IP: fdd6:3807:b7da::15 the v4 IP is 192.8.192.15 so I tried to keep the same numbering so to speak.

    It's static IPv6 address - fdd6:3807:b7da::15/48
    3ccbff8e-d3f5-491b-9cc3-9cb362d85ced-image.png
    I took care of disabling the "block private network option"
    b530d8e1-197e-4502-9ae1-6f31af83ad84-image.png

    I enabled the DHCPv6 and the RA deamon, because I have SLAAC and stateful clients in my LAN. I took a blind guess in creating the range:
    7efcb650-da52-4a21-9677-ba7f748bea0e-image.png
    And I'm sending the RA as managed per choice:
    dfa52f1e-d068-4c3e-a5ec-fb1a34c99e66-image.png

    As it stands today, a host in the LAN obtains the follow IPv6 address:
    inet6 fdd6:3807:b7da:0:20c:29ff:fee7:c7d6 prefixlen 64 scopeid 0x0<global>

    In the routing table of the host, I don't see the result of the RA:
    ip -6 route
    unreachable ::/96 dev lo metric 1024 error -113
    unreachable ::ffff:0.0.0.0/96 dev lo metric 1024 error -113
    unreachable 2002:a00::/24 dev lo metric 1024 error -113
    unreachable 2002:7f00::/24 dev lo metric 1024 error -113
    unreachable 2002:a9fe::/32 dev lo metric 1024 error -113
    unreachable 2002:ac10::/28 dev lo metric 1024 error -113
    unreachable 2002:c0a8::/32 dev lo metric 1024 error -113
    unreachable 2002:e000::/19 dev lo metric 1024 error -113
    unreachable 3ffe:ffff::/32 dev lo metric 1024 error -113
    fdd6:3807:b7da::/64 dev FO proto kernel metric 256 expires 86396sec
    fe80::/64 dev FO proto kernel metric 256
    default via fe80::20c:29ff:fe27:7e2e dev FO proto ra metric 1024 expires 56sec hoplimit 64

    Content of the RA:
    615be958-a65d-41b2-a418-26abb5f70a04-image.png aa77d695-35fb-4911-b979-4602c8dd0ba2-image.png

    Judging by the ip 6 routing table my RA is not taken into account as the default route. Is there something I must change on my RA or on my device ? (centos 7.6)?



  • To the ones that may have the same problem as me, I managed to go a little further. To allow incoming ICMPv6 ping messages I had to uncheck those two options on my interface:
    8d0c7aec-55ca-44c1-a620-957d549360ae-image.png

    I'm still having a problem with my Cisco SG250-26 which does not let some IPv6 packets passing through...


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