CARP VIP link local vs IPv6 communication

[Patrick M. Hausen]

What's the reason for that change?

[Monviech (Cedrik)]

The mvc migration of the component.

The old code at that spot was very unfortunate.

[GreenMatter]

There is no bug here the field exists and you can input the source IP address.

That's what I'd done also (i.e. I typed in: fe80::14) and doesn't work. Once I remove CARP VIPs ipv6 works fine.

My issue may have something to do with tunnelbroker setup, as I don't have native ipv6 provider available... OR I will try also to reconfigure my PVE setup and create additional LAN bridge for backup instance and instead of having them (2x opnsense) connected over single linux bridge - within proxmox, connect them over physical switch?
This of course requires second downlink, so:

• regular bridge would remain connected as it is now
• backup/new bridge will be connected to switch via additional downlink

[Monviech (Cedrik)]

If it does not work in your infrastructure it does not mean it's bug right away.

Check for these:
- If you set a source address for the RAs, but "cat /var/etc/radvd.conf" does not contain it.
- If you set a source address for the RAs, and packet capture that the source address of the RAs (Source link layer option) is not the source address you set.

Please note that depending on your interface configuration on LAN or whatever you use, (Static IPv6, Track Interface, Identity Association) radvd.conf will contains subtly different results.

Best use the new "Identity Association" as IPv6 configuration method.

[GreenMatter]

Check for these:
- If you set a source address for the RAs, but "cat /var/etc/radvd.conf" does not contain it.
- If you set a source address for the RAs, and packet capture that the source address of the RAs (Source link layer option) is not the source address you set.

radvd.conf contains source address:

Code Select Expand

[color=#000000][size=1][font=Menlo][/font][/size][/color]
interface vlan14 {
    AdvSendAdvert on;
    MinRtrAdvInterval 200;
    MaxRtrAdvInterval 600;
    AdvLinkMTU 1500;
    AdvDefaultPreference high;
    AdvRASrcAddress {        fe80::14;
    };
    AdvSourceLLAddress off;
    RemoveAdvOnExit off;
    prefix XXXXXXXXd:4::/64 {        DeprecatePrefix off;
        AdvOnLink on;
        AdvAutonomous on;
    };
    RDNSS XXXXXXXXXd:1::4 {    };
    DNSSL x.xx {    };
};

and tcpdump of RA:

Code Select Expand

tcpdump -i vlan14 -vv -n icmp6 and 'ip6[40] == 134'

tcpdump: listening on vlan14, link-type EN10MB (Ethernet), snapshot length 262144 bytes11:17:40.481739 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 112) fe80::14 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 112
hop limit 64, Flags [other stateful], pref high, router lifetime 1800s, reachable time 0ms, retrans timer 0ms
  prefix info option (3), length 32 (4): XXXXXXXXXd:4::/64, Flags [onlink, auto], valid time 86400s, pref. time 14400s
    0x0000:  40c0 0001 5180 0000 3840 0000 0000 2001
    0x0010:  0470 604d 0004 0000 0000 0000 0000
  rdnss option (25), length 24 (3):  lifetime 1800s, addr: XXXXXXXd:1::4
    0x0000:  0000 0000 0708 2001 0470 604d 0001 0000
    0x0010:  0000 0000 0004
  dnssl option (31), length 32 (4):  lifetime 1800s, domain(s): x.xx.
    0x0000:  0000 0000 0708 0d6d 6172 737a 616c 6b6f
    0x0010:  7773 6379 0270 6c00 0000 0000 0000
  mtu option (5), length 8 (1):  1500
    0x0000:  0000 0000 05dc

Like I wrote in my first message: 

But as I use tunnelbroker I can't use my ipv4 WAN interface to set up CARP VIP (https://docs.opnsense.org/manual/how-tos/carp.html#setup-virtual-ipv6-global-unicast-address) and I think this should have been my GIF interface...(?) And if I set next hop, either tunnel remote or local address as CARP VIP address, VIP remains as disabled...

This could have been my source of this issue, but I'm not sure how to solve it.

[GreenMatter]

An update: out of blue (almost) ipv6 started working! My guess is that is because of "routes" - I had them configured in my previous setup. I deleted them from RA when preparing HA setup, but maybe my laptop had cached them (?)... Anyway, since couple of hours ago it did start working and continue doing so...