danmcd, is it embedded in the ipv6 stack to use a local ULA address first when reaching a remote ULA address, even when not on the same subnet?

I'm not sure off the top of my head. I'd need to dig or experiment. I'd guess the answer would be, "depends on the routing table".

Yeah, I think so as well.

ULA addresses will need to be encapsulated somehow if it's going to traverse the public Internet.

So I work from home full time, and am trying to get ULA working across different VLANs in combination with the /48 that I DHCPv6 PD'd

I'm under the impression that it should first consider if it is a ULA address, blog.apnic.net/2020/05/20/getting-ipv6-private-addressing-right

(With the /48 GOA addresses...)

If you've got ULA at work and one at home, then I'd suggest a VPN between the two, and have your vpn router on the ULA network with a route to the remote network pointed at the vpn

my impression is that it's up to whoever manages a router to determine how/if ULA addresses should be forwarded

I also don't ever rely on magic in the neworking stack when I can make it explicit in the routing table.

But neither ULA sources nor ULA destinations are going to work traversing the public internet. So you're going to need at minimum 6in4, 6in6, GRE, or a VPN.

These aren't even traversing the internet, just being routed locally, but every VLAN has ULA and GOA addresses, but local DNS for servers points towards ULA addresses

I noticed that even when not on the same subnet, it picks a ULA source address to communicate to it

The simple test is :

route get <dst>

see what link is matched.

Oh...

$UTS/common/inet/ip/ip6_asp.c ==> Address Selection Policy! :)

Check there @copec. :

:)

oh, very interesting

@wiedi updated it in 2017.

bahamat - Yeah, I feel the same way, I would rather box something in so that I know. Reading about it though, ULA is supposed to fulfill what RFC1918 addresses did for consistent network numbering, but instead of being NAT'd be parallel with global addresses, which implied to me that source address selection would have to take precedence over route selection for that to work

[illumos-gate] 15816 Want GLDv3 plumbing for 200/400Gb Ethernet -- Robert Mustacchi <rm⊙fo>

Consequently, that makes more sense why you would always want to use a link-local address default gateway, so it doesn't force a routing decision when you want to pick a local ULA address to reach a remote ULA address, and the same for GOA addresses

sorry, I'll keep the noise down :-p

copec: you can tweak the logic with illumos.org/man/8/ipaddrsel but I think our defaults should be pretty good

hrm..

[illumos-gate] 15915 Want SMBIOS 3.7 support -- Robert Mustacchi <rm⊙fo>

the labelling in the default ipaddrsel table has some throwbacks