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  • 1.  Multiple IPv6 Addresses per Interface

    Posted 12-13-2012 07:21

    Please tell me what the problem?

     

    show configuration interfaces xe-0/0/1
    unit 0 {
    description Localnet;
    family inet6 {
    address 2001:590:3803::1/64;
    address 2a00:1ca8:2c::1/64;
    }
    }

     

    show interfaces xe-0/0/1
    Physical interface: xe-0/0/1, Enabled, Physical link is UpProtocol inet6, MTU: 1500

    Addresses, Flags: Is-Preferred Is-Primary
    Destination: 2001:590:3803::/64, Local: 2001:590:3803::1
    Addresses, Flags: Is-Preferred Duplicate
    Destination: 2a00:1ca8:2c::/64, Local: 2a00:1ca8:2c::1

     

    show route 2a00:1ca8:2c::1

    inet6.0: 76686 destinations, 153245 routes (76686 active, 0 holddown, 1 hidden)
    + = Active Route, - = Last Active, * = Both

    2a00:1ca8:2c::/48 *[Static/5] 1d 14:57:52
    Discard

     

    ping 2a00:1ca8:2c::1
    PING6(56=40+8+8 bytes) 2001:590:3803::2 --> 2a00:1ca8:2c::1
    ping: sendmsg: Can't assign requested address
    ping6: wrote 2a00:1ca8:2c::1 16 chars, ret=-1
    ping: sendmsg: Can't assign requested address
    ping6: wrote 2a00:1ca8:2c::1 16 chars, ret=-1
    ^C
    --- 2a00:1ca8:2c::1 ping6 statistics ---
    2 packets transmitted, 0 packets received, 100% packet loss

     

     

    "A single interface may also have multiple IPv6 addresses of any type(unicast, anycast, and multicast) or scope" ----quoted form RFC 4291

     



  • 2.  RE: Multiple IPv6 Addresses per Interface
    Best Answer

    Posted 12-13-2012 13:14

    The interface address that is on the same ipv6 network as your ping destination (2a00:1ca8:2c::1) has "duplicate" flag there.  I suspect this is preventing the kernel and ping from being able to use the correct source IP.

     

    Duplicate Address Detection is run, as part of IPv6 Neighbor Discovery protocol.  It seems another device on this link is, or was, configured for the same address.  Once that is corrected, you might have to deactivate/activate the interface to remove that flag.

    Once you've verified no duplicates, and the flag is removed, you might also consider specifying the source address of the ping.

     

    Regards,

    Ben

     

     

     



  • 3.  RE: Multiple IPv6 Addresses per Interface

    Posted 12-13-2012 13:35

    Really simple.
    Obviously, "unknown" client took the address, which was a bit unexpected.
    Changing ipv6 solved the problem.

     

    Addresses, Flags: Is-Preferred Is-Primary
    Destination: 2001:590:3803::/64, Local: 2001:590:3803::1
    Addresses, Flags: Is-Preferred
    Destination: 2a00:1ca8:2c::/64, Local: 2a00:1ca8:2c::3
    Addresses, Flags: Is-Preferred

     

    ping6 2a00:1ca8:2c::3
    PING 2a00:1ca8:2c::3(2a00:1ca8:2c::3) 56 data bytes
    64 bytes from 2a00:1ca8:2c::3: icmp_seq=1 ttl=54 time=150 ms
    64 bytes from 2a00:1ca8:2c::3: icmp_seq=2 ttl=54 time=150 ms
    64 bytes from 2a00:1ca8:2c::3: icmp_seq=3 ttl=54 time=149 ms

    --- 2a00:1ca8:2c::3 ping statistics ---
    3 packets transmitted, 3 received, 0% packet loss, time 2000ms
    rtt min/avg/max/mdev = 149.458/150.034/150.489/0.620 ms


    The problem is closed.