Re: ipv6 gateway on different subnet

[Greg Troxel <gdt%lexort.com@localhost>]

Christof Meerwald <cmeerw%cmeerw.org@localhost> writes:

> On Tue, Jan 21, 2025 at 08:31:58PM -0600, Peter Miller wrote:

> And comparing the neighbor advertisements:
>
> Debian
>> 10:33:23.197053 00:16:3e:d7:cf:50 > d8:67:d9:58:3d:1b, ethertype
>> IPv6 (0x86dd), length 86: (hlim 255, next-header ICMPv6 (58) payload
>> length: 32) 2602:fed2:7116:d82c::5 > fe80::da67:d9ff:fe58:3d1b:
>> [icmp6 sum ok] ICMP6, neighbor advertisement, length 32, tgt is
>> 2602:fed2:7116:d82c::5, Flags [solicited, override]
>
> NetBSD
>> 05:01:13.467620 00:16:3e:d7:cf:50 > d8:67:d9:58:3d:1b, ethertype
>> IPv6 (0x86dd), length 86: (hlim 255, next-header ICMPv6 (58) payload
>> length: 32) fe80::216:3eff:fed7:cf50 > fe80::da67:d9ff:fe58:3d1b:
>> [icmp6 sum ok] ICMP6, neighbor advertisement, length 32, tgt is
>> 2602:fed2:7116:d82c::6, Flags [solicited, override]
>
> I am seeing this difference:
>
> 2602:fed2:7116:d82c::5 > fe80::da67:d9ff:fe58:3d1b
> vs.
> fe80::216:3eff:fed7:cf50 > fe80::da67:d9ff:fe58:3d1b

See netinet6/nd6_nbr.c and netinet6/nd6_rtr.c which might be
enlightening.

Use "ndp -a" and "netstat -nr" to see what's in the routing table.

Do "netstat -s", wait, and do it again, saving both results, and diff
-U0 to see all changed counters, including ones you aren't expecting.