Re: ipv6 gateway on different subnet

Here's some network traffic, without running anything else

doas tcpdump -npi vioif0 icmp6
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on vioif0, link-type EN10MB (Ethernet), capture size 262144 bytes
10:33:54.720876 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:2: ICMP6,
neighbor solicitation, who has 2604:f440:3:c::2, length 32
10:33:55.086333 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:6: ICMP6,
neighbor solicitation, who has 2602:2c8::6, length 32
10:33:55.756262 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:3: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:112::3, length 32
10:33:55.804371 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:3: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:112::3, length 32
10:33:56.141429 IP6 2602:fed2:7116::53b5:fcaf > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:fed2:7116::1, length 32
10:33:56.757464 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:3: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:112::3, length 32
10:33:56.804408 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:3: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:112::3, length 32
10:33:58.707368 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:2898::1, length 32
10:33:59.375111 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ffb5:db11:
ICMP6, neighbor solicitation, who has
2602:fed2:7116:0:1:63fa:f8b5:db11, length 32
10:34:00.319785 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:5: ICMP6,
neighbor solicitation, who has 2602:2c8::5, length 32
10:34:00.375649 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ffb5:db11:
ICMP6, neighbor solicitation, who has
2602:fed2:7116:0:1:63fa:f8b5:db11, length 32
10:34:00.967571 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:101e::1, length 32
10:34:01.268551 IP6 2602:2c8:0:22ee::1 > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8::1, length 32
10:34:01.320663 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:5: ICMP6,
neighbor solicitation, who has 2602:2c8::5, length 32
10:34:03.564547 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:34:03.565614 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:34:03.566002 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:34:03.792946 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:1::1, length 32
10:34:03.924594 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:34:03.925099 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:34:04.495062 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:3: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:112::3, length 32
10:34:04.565351 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:34:04.565729 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:34:04.566591 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:34:04.793486 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:1::1, length 32
10:34:04.926108 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:34:04.926494 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
^C
27 packets captured
1847 packets received by filter
0 packets dropped by kernel


with this running and connection is good
ping6 -S 2602:fed2:7116:d82c::1 google.com

doas tcpdump -npi vioif0 icmp6
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on vioif0, link-type EN10MB (Ethernet), capture size 262144 bytes
10:35:43.513666 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:6: ICMP6,
neighbor solicitation, who has 2602:2c8::6, length 32
10:35:43.531878 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:0: ICMP6,
neighbor solicitation, who has 2604:f440:3:17::, length 32
10:35:43.554989 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:35:43.555442 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:35:43.555873 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:35:43.739427 IP6 2602:fed2:7116:d82c::1 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 0, length 16
10:35:43.741260 IP6 2607:f8b0:4023:1002::71 > 2602:fed2:7116:d82c::1:
ICMP6, echo reply, seq 0, length 16
10:35:43.803312 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff88:138e:
ICMP6, neighbor solicitation, who has 2602:fed2:7116::f88:138e, length
32
10:35:43.939558 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:3: ICMP6,
neighbor solicitation, who has 2604:f440:3:c::3, length 32
10:35:44.525532 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff90:168f:
ICMP6, neighbor solicitation, who has
2602:f94c:5d:c970:3258:c675:5790:168f, length 32
10:35:44.554355 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:35:44.554829 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:35:44.555235 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:35:44.751161 IP6 2602:fed2:7116:d82c::1 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 1, length 16
10:35:44.753006 IP6 2607:f8b0:4023:1002::71 > 2602:fed2:7116:d82c::1:
ICMP6, echo reply, seq 1, length 16
10:35:44.928643 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff6b:56d7:
ICMP6, neighbor solicitation, who has 2602:2c8:0:2a9d::666b:56d7,
length 32
10:35:45.760209 IP6 2602:fed2:7116:d82c::1 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 2, length 16
10:35:45.762063 IP6 2607:f8b0:4023:1002::71 > 2602:fed2:7116:d82c::1:
ICMP6, echo reply, seq 2, length 16
10:35:46.759171 IP6 2602:fed2:7116:d82c::1 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 3, length 16
10:35:46.761022 IP6 2607:f8b0:4023:1002::71 > 2602:fed2:7116:d82c::1:
ICMP6, echo reply, seq 3, length 16
10:35:47.758140 IP6 2602:fed2:7116:d82c::1 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 4, length 16
10:35:47.759976 IP6 2607:f8b0:4023:1002::71 > 2602:fed2:7116:d82c::1:
ICMP6, echo reply, seq 4, length 16


on the other address with 100% packet loss
ping6 -S 2602:fed2:7116:d82c::2 google.com

10:37:17.595359 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:0: ICMP6,
neighbor solicitation, who has 2604:f440:3:17::, length 32
10:37:17.851412 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 0, length 16
10:37:18.864750 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 1, length 16
10:37:19.873822 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 2, length 16
10:37:20.872779 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 3, length 16
10:37:21.871745 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 4, length 16
10:37:21.874248 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:2: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:d82c::2, length 32
10:37:21.874304 IP6 fe80::216:3eff:fed7:cf50 >
fe80::da67:d9ff:fe58:3d1b: ICMP6, neighbor advertisement, tgt is
2602:fed2:7116:d82c::2, length 32
10:37:22.102207 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:37:22.622296 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:37:22.870697 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 5, length 16
10:37:22.873565 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:2: ICMP6,
neighbor solicitation, who has 2602:fed2:7116:d82c::2, length 32
10:37:22.873611 IP6 fe80::216:3eff:fed7:cf50 >
fe80::da67:d9ff:fe58:3d1b: ICMP6, neighbor advertisement, tgt is
2602:fed2:7116:d82c::2, length 32
10:37:22.988273 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:37:23.028055 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:37:23.625797 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:37:23.649027 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:37:23.859172 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:0: ICMP6,
neighbor solicitation, who has 2604:f440:3:17::, length 32
10:37:23.869672 IP6 2602:fed2:7116:d82c::2 > 2607:f8b0:4023:1002::71:
ICMP6, echo request, seq 6, length 16
10:37:23.990248 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:37:24.027340 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1027::1, length 32
10:37:24.413802 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:103f::1, length 32
10:37:24.649646 IP6 fe80::da67:d9ff:fe58:3d1b > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:2c8:0:1007::1, length 32
10:37:24.669056 IP6 2602:fed2:7116::5439:ba38 > ff02::1:ff00:1: ICMP6,
neighbor solicitation, who has 2602:fed2:7116::1, length 32


-- 
Thanks
Peter