Help Understanding why my ipv6 connection no longer works

[kingamajick]

That is a link-local EUI-64 address that is derived from the MAC of the gateway. The MAC OUI seems to be D4:66:24, so that mean there is Cisco equipment on the other side. You should be able to ping that address, at least if you suffix it with an interface name: "ping fe80::d666:24ff:fe5b:e4db%vtnet0".

You are on a Proxmox VM, so have you disabled the Proxmox firewall for vtnet0?

What looks strange is that this does not seem to be a default route?

Re the default route, it is at least according to System -> Routes -> Status (so I assume this would be the default shown in Interfaces -> Overview -> Details)

[meyergru]

My Interfaces: Overview looks mostly the same. Apparently, the gateway is the link-local-address of the ISP router, whereas the IPv6 route uses the LL prefix fe80::/64 to route that over pppoe0.

So, the route setup seems right, but neither your WAN nor your LAN has a GUA IPv6.

I found that with some ISPs, I had to play around with "send prefix hint" an "request prefix only" combinations, because they only supported a certain setting and did not answer at all when it did not conform to that. It does not really matter what they will provide, it they at least hand out a /56 prefix, because you can assign that to the WAN as well and that will even work better for dyndns purposes.

I would try all combinations and see what GUA you get for LAN and WAN (or look at the logs and see if you get IA_NA and IA_PD).

[kingamajick]

I'll give that a go later, although I did confirm with there technical support last night that I should be expecting a /48 PD delegation, but at this pint anything is worth a try :)

[meyergru]

It might well be that if you request the wrong prefix size, they will deny that, too.

[kingamajick]

Looking into the package capture, is the the solicit and the advertisement response of DHCPv6?


WAN vtnet0 2025-02-12 11:52:11.727627 80:xx:xx:xx:xx:xx d4:66:24:5b:e4:db
ethertype IPv6 (0x86dd), length 86: (hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has fe80::d666:24ff:fe5b:e4db
     source link-address option (1), length 8 (1): 80:xx:xx:xx:xx:xx
       0x0000:  8069 1a76 529b

WAN vtnet0 2025-02-12 11:52:11.744065 d4:66:24:5b:e4:db 80:xx:xx:xx:xx:xx
ethertype IPv6 (0x86dd), length 86: (class 0xe0, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, neighbor advertisement, length 32, tgt is fe80::d666:24ff:fe5b:e4db, Flags [router, solicited, override]
     destination link-address option (2), length 8 (1): d4:66:24:5b:e4:db
       0x0000:  d466 245b e4db

This is followed by this:


WAN
vtnet0   2025-02-12
11:52:11.938877   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4205
WAN
vtnet0   2025-02-12
11:52:11.940055   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4205
WAN
vtnet0   2025-02-12
11:52:12.966498   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4206
WAN
vtnet0   2025-02-12
11:52:12.967682   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4206
WAN
vtnet0   2025-02-12
11:52:14.008721   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4207
WAN
vtnet0   2025-02-12
11:52:14.010783   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4207
WAN
vtnet0   2025-02-12
11:52:15.022620   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4208
WAN
vtnet0   2025-02-12
11:52:15.023689   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4208
WAN
vtnet0   2025-02-12
11:52:16.072503   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4209
WAN
vtnet0   2025-02-12
11:52:16.073848   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4209
WAN
vtnet0   2025-02-12
11:52:17.120092   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4210
WAN
vtnet0   2025-02-12
11:52:17.121742   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4210
WAN
vtnet0   2025-02-12
11:52:18.192674   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4211
WAN
vtnet0   2025-02-12
11:52:18.193722   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4211
WAN
vtnet0   2025-02-12
11:52:19.222559   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4212
WAN
vtnet0   2025-02-12
11:52:19.223691   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4212
WAN
vtnet0   2025-02-12
11:52:20.246402   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4213
WAN
vtnet0   2025-02-12
11:52:20.247535   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4213
WAN
vtnet0   2025-02-12
11:52:21.258802   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4214
WAN
vtnet0   2025-02-12
11:52:21.260060   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4214
WAN
vtnet0   2025-02-12
11:52:21.871791   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 86: (class 0xe0, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has fe80::8269:1aff:fe76:529b
     source link-address option (1), length 8 (1): d4:66:24:5b:e4:db
       0x0000:  d466 245b e4db
WAN
vtnet0   2025-02-12
11:52:21.871818   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 78: (hlim 255, next-header ICMPv6 (58) payload length: 24) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is fe80::8269:1aff:fe76:529b, Flags [router, solicited]
WAN
vtnet0   2025-02-12
11:52:22.288753   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4215
WAN
vtnet0   2025-02-12
11:52:22.289967   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4215
WAN
vtnet0   2025-02-12
11:52:23.307621   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4216
WAN
vtnet0   2025-02-12
11:52:23.308690   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4216
WAN
vtnet0   2025-02-12
11:52:24.322136   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4217
WAN
vtnet0   2025-02-12
11:52:24.323097   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4217
WAN
vtnet0   2025-02-12
11:52:25.372505   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4218
WAN
vtnet0   2025-02-12
11:52:25.373694   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4218
WAN
vtnet0   2025-02-12
11:52:26.394745   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4219
WAN
vtnet0   2025-02-12
11:52:26.396060   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4219
WAN
vtnet0   2025-02-12
11:52:27.414085   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4220
WAN
vtnet0   2025-02-12
11:52:27.415322   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4220
WAN
vtnet0   2025-02-12
11:52:28.458791   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4221
WAN
vtnet0   2025-02-12
11:52:28.460026   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4221
WAN
vtnet0   2025-02-12
11:52:29.469843   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4222
WAN
vtnet0   2025-02-12
11:52:29.471429   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4222
WAN
vtnet0   2025-02-12
11:52:30.517364   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, echo request, id 18980, seq 4223
WAN
vtnet0   2025-02-12
11:52:30.518600   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 63: (hlim 64, next-header ICMPv6 (58) payload length: 9) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, echo reply, id 18980, seq 4223
WAN
vtnet0   2025-02-12
11:52:30.858885   80:xx:xx:xx:xx:xx   d4:66:24:5b:e4:db   ethertype IPv6 (0x86dd), length 86: (hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::8269:1aff:fe76:529b > fe80::d666:24ff:fe5b:e4db: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has fe80::d666:24ff:fe5b:e4db
     source link-address option (1), length 8 (1): 80:xx:xx:xx:xx:xx
       0x0000:  8069 1a76 529b
WAN
vtnet0   2025-02-12
11:52:30.883867   d4:66:24:5b:e4:db   80:xx:xx:xx:xx:xx   ethertype IPv6 (0x86dd), length 86: (class 0xe0, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::d666:24ff:fe5b:e4db > fe80::8269:1aff:fe76:529b: [icmp6 sum ok] ICMP6, neighbor advertisement, length 32, tgt is fe80::d666:24ff:fe5b:e4db, Flags [router, solicited, override]
     destination link-address option (2), length 8 (1): d4:66:24:5b:e4:db
       0x0000:  d466 245b e4db

[meyergru]

Those are only router advertisements and ping requests and replies, you do not seem to get any DHCPv6 replies, nor do you send requests.

That would explain why you only get a route and a link-local address. Then again, the DHCPv6 exchange may have happened before the dump starts.

[kingamajick]

Ah got it thanks, is there any way to force OPNsense to request DHCPv6 while I have package capture enabled?

[meyergru]

I would try to disable and enable the interface or disable DHCPv6 and then re-enable. IDK if the running tcpdump will suvive that, however.

[kingamajick]

root@router:/home/kingamajick # tcpdump -i vtnet0 -Avvv '(port 546 or port 547)'
tcpdump: listening on vtnet0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
14:48:04.822436 IP6 (hlim 1, next-header UDP (17) payload length: 89) fe80::8269:1aff:fe76:529b.dhcpv6-client > ff02::1:2.dhcpv6-server: [udp sum ok] dhcp6 solicit (xid=d8e126 (client-ID hwaddr/time type 1 time 748624729 22eb3b4e0e98) (elapsed-time 65535) (option-request DNS-server DNS-search-list) (IA_PD IAID:0 T1:0 T2:0 (IA_PD-prefix ::/48 pltime:4294967295 vltime:4294967295)))
`....Y...........i...vR..................".#.YFd...&........,..Y".;N...................)........................0................

No response to the solicit at all, I'll give it a try this evening to iterate though the prefix options and see If I have any luck.

[meyergru]

Then again, the internet is full of reports on CF IPv6 problems, like this: https://forums.thinkbroadband.com/fibre/4697990-community-fibre-ipv6-or-lack-of-it.html

What many people will tell you is that DHCPv6 requests are being ignored then the MAC does not match what CF thinks it should be. You can ask them to clear that on their side. Also, with DHCPv6, it is usually a DUUID, which is derived from the MAC, but IDK exactly.

[kingamajick]

Well after doing absolutely nothing for a few days, ipv6 is working I have the prefix shown in the settings -> overview -> more details. So I guess the issue was somewhere on there end. Thanks for all the help @meyergru really appreciate it!