IPv6 auto-configuration not able to resolve the IPv6 default gateway.

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IPv6 auto-configuration not able to resolve the IPv6 default gateway.

Software Mac OS X Lion 10.7.4 (11E53)

I observed that I am receiving IPv6 Router-advertisements from the router which has VRRP configured on the default gateway. If i remove the IPv6 VRRP configuration from my router and have it connected to a IPv6 interface (i.e. physical IP) the autoconfiguration works just fine and am able to resolve the IPv6 addresses.

With the same IPv6 VRRP configuration all other OS are able to resolve the IPv6 configuration:

Windows7

Ubuntu

Red Hat Linux

FreeBSD

Fedora

On the MAC i ensured that the

xxxxx-MacBook-Pro:~ xxxxx$ sysctl -a | grep net.inet6.ip6.accept_rtadv

net.inet6.ip6.accept_rtadv: 1

xxxxx-MacBook-Pro:~ xxxxx$ sysctl -a | grep net.inet6.ip6.use_tempaddr

net.inet6.ip6.use_tempaddr: 1

This is the router-advertisment being received by the MACbook pro but IPv6 address not getting resolved. The same is also the case with MAC OS Mountain Lion.

Am i missing something. Please help urgently since I have to have the MACbookpro for our new office online and working on thursday.

<--RA from the interface without VRRP configuredNo.     Time        Source                Destination           Protocol Length Info
     15 2.251188    fe80::2ac0:daff:fefd:6ff0 ff02::1               ICMPv6   110    Router Advertisement from 28:c0:da:fd:6f:f0

Frame 15: 110 bytes on wire (880 bits), 110 bytes captured (880 bits)
    Arrival Time: Aug 19, 2012 16:26:49.524019000 PDT
    Epoch Time: 1345418809.524019000 seconds
    [Time delta from previous captured frame: 0.169898000 seconds]
    [Time delta from previous displayed frame: 0.169898000 seconds]
    [Time since reference or first frame: 2.251188000 seconds]
    Frame Number: 15
    Frame Length: 110 bytes (880 bits)
    Capture Length: 110 bytes (880 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:icmpv6]
    [Coloring Rule Name: ICMP]
    [Coloring Rule String: icmp || icmpv6]
Ethernet II, Src: JuniperN_fd:6f:f0 (28:c0:da:fd:6f:f0), Dst: IPv6mcast_00:00:00:01 (33:33:00:00:00:01)
    Destination: IPv6mcast_00:00:00:01 (33:33:00:00:00:01)
        Address: IPv6mcast_00:00:00:01 (33:33:00:00:00:01)
        .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
        .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
    Source: JuniperN_fd:6f:f0 (28:c0:da:fd:6f:f0)
        Address: JuniperN_fd:6f:f0 (28:c0:da:fd:6f:f0)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: fe80::2ac0:daff:fefd:6ff0 (fe80::2ac0:daff:fefd:6ff0), Dst: ff02::1 (ff02::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 56
    Next header: ICMPv6 (0x3a)
    Hop limit: 255
    Source: fe80::2ac0:daff:fefd:6ff0 (fe80::2ac0:daff:fefd:6ff0)
    [Source SA MAC: JuniperN_fd:6f:f0 (28:c0:da:fd:6f:f0)]
    Destination: ff02::1 (ff02::1)
Internet Control Message Protocol v6
    Type: Router Advertisement (134)
    Code: 0
    Checksum: 0x1908 [correct]
    Cur hop limit: 64
    Flags: 0x00
        0... .... = Managed address configuration: Not set
        .0.. .... = Other configuration: Not set
        ..0. .... = Home Agent: Not set
        ...0 0... = Prf (Default Router Preference): Medium (0)
        .... .0.. = Proxy: Not set
        .... ..0. = Reserved: 0
    Router lifetime (s): 12
    Reachable time (ms): 0
    Retrans timer (ms): 0
    ICMPv6 Option (Source link-layer address : 28:c0:da:fd:6f:f0)
        Type: Source link-layer address (1)
        Length: 1 (8 bytes)
        Link-layer address: JuniperN_fd:6f:f0 (28:c0:da:fd:6f:f0)
    ICMPv6 Option (Prefix information : 2012:db9:0:56::/64)
        Type: Prefix information (3)
        Length: 4 (32 bytes)
        Prefix Length: 64
        Flag: 0xc0
            1... .... = On-link flag(L): Set
            .1.. .... = Autonomous address-configuration flag(A): Set
            ..0. .... = Router address flag(R): Not set
            ...0 0000 = Reserved: 0
        Valid Lifetime: 2592000
        Preferred Lifetime: 604800
        Reserved
        Prefix: 2012:db9:0:56:: (2012:db9:0:56::)

<--RA from the interface with VRRP configured

No.     Time        Source                Destination           Protocol Length Info
     24 2.801947    fe80:1000:0:1000::10  ff02::1               ICMPv6   118    Router Advertisement from 00:00:5e:00:02:01

Frame 24: 118 bytes on wire (944 bits), 118 bytes captured (944 bits)
    Arrival Time: Aug 19, 2012 16:28:24.420179000 PDT
    Epoch Time: 1345418904.420179000 seconds
    [Time delta from previous captured frame: 0.105898000 seconds]
    [Time delta from previous displayed frame: 0.105898000 seconds]
    [Time since reference or first frame: 2.801947000 seconds]
    Frame Number: 24
    Frame Length: 118 bytes (944 bits)
    Capture Length: 118 bytes (944 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:icmpv6]
    [Coloring Rule Name: ICMP]
    [Coloring Rule String: icmp || icmpv6]
Ethernet II, Src: JuniperN_18:97:f0 (f8:c0:01:18:97:f0), Dst: IPv6mcast_00:00:00:01 (33:33:00:00:00:01)
    Destination: IPv6mcast_00:00:00:01 (33:33:00:00:00:01)
        Address: IPv6mcast_00:00:00:01 (33:33:00:00:00:01)
        .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
        .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
    Source: JuniperN_18:97:f0 (f8:c0:01:18:97:f0)
        Address: JuniperN_18:97:f0 (f8:c0:01:18:97:f0)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: fe80:1000:0:1000::10 (fe80:1000:0:1000::10), Dst: ff02::1 (ff02::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 64
    Next header: ICMPv6 (0x3a)
    Hop limit: 255
    Source: fe80:1000:0:1000::10 (fe80:1000:0:1000::10)
    Destination: ff02::1 (ff02::1)
Internet Control Message Protocol v6
    Type: Router Advertisement (134)
    Code: 0
    Checksum: 0x4976 [correct]
    Cur hop limit: 64
    Flags: 0x00
        0... .... = Managed address configuration: Not set
        .0.. .... = Other configuration: Not set
        ..0. .... = Home Agent: Not set
        ...0 0... = Prf (Default Router Preference): Medium (0)
        .... .0.. = Proxy: Not set
        .... ..0. = Reserved: 0
    Router lifetime (s): 0
    Reachable time (ms): 0
    Retrans timer (ms): 0
    ICMPv6 Option (Source link-layer address : 00:00:5e:00:02:01)
        Type: Source link-layer address (1)
        Length: 1 (8 bytes)
        Link-layer address: UscInfor_00:02:01 (00:00:5e:00:02:01)
    ICMPv6 Option (MTU : 1500)
        Type: MTU (5)
        Length: 1 (8 bytes)
        Reserved
        MTU: 1500
    ICMPv6 Option (Prefix information : 2620:0:1000:2505::/64)
        Type: Prefix information (3)
        Length: 4 (32 bytes)
        Prefix Length: 64
        Flag: 0xc0
            1... .... = On-link flag(L): Set
            .1.. .... = Autonomous address-configuration flag(A): Set
            ..0. .... = Router address flag(R): Not set
            ...0 0000 = Reserved: 0
        Valid Lifetime: 2592000
        Preferred Lifetime: 604800
        Reserved
        Prefix: 2620:0:1000:2505:: (2620:0:1000:2505::)

MacBook Pro, Mac OS X (10.7)

Posted on Aug 20, 2012 2:41 AM

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Answer 1

Jul 3, 2015 4:04 PM in response to adipv6

Hey there,

I Noticed this too and found your post searching for it.

I know this topic is 3 years old and I hope u have found the solution already but for the people who find this topic and havent, this is the solution:

For VRRP to work on a Cisco switch (or any switch) u have to use Link-local adresses.
In the first RFC's explaining Link Local adresses, there is no mention of which bits can and can't be used.
This is detailed in one of the later RFC's: https://tools.ietf.org/html/rfc4291#section-2.5.6

In this RFC it states that the first 10 bits are set (FE80), the next 54 bits have to be 0 and the host portion can be changed as needed.

In my case i used a link local address which was build up like FE80:xxxx:xxxx:xxxx::1, which does use the 54 bits that need to be 0.

Cisco equipment doesn't forbid to use this notation and as it was more similar to the used public ipv6 address, so i used it. SLAAC worked for all clients except mac's. After some troubleshooting i pinned it down to this explanation, changed it and it works like a charm now. Seems Apple is the only one sticking to this RFC 🙂

Hope it helps.

With kind regards....

David

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