I'm moving my first steps in IPv6 in general and with OmniOS in particular! :) I've been assigned a static IPv6 and a default router by by hosting provider. It got me a while to understand that I need to get a link-local address before I can configure the static IP over a NIC... it's right?

Yes, you always need the link-local. So if you're using ipadm you'll need to

ipadm create-addr -T addrconf ...

before setting up the main address with

ipadm create-addr -T static ...

I'm still waiting for my ISP to enter the IPv6 world, we had everything on IPv6 at one of my previous employers but that was about 10 years ago so I haven't used Ipv6 in a while

ok, thanks. Now there is a thing that I do not understand: my hosting provider assigned me a static address with a /128 prefix and the IPv6 address of the default router. But /128 is what web called /32 in IPv4... how the heck I can reach the default router with suck a netmask?! In fact as soon as I try to add a default inet6 route it returns me

that "network is unreachable"

I've queried via WHOIS my static IP and I read that it's allocation has been within a /44 subnet. So I configured this:

I would expect that the /128 refers to the size of the block of addresses they've allocated to you (ie, that there's only one) rather than the mask

Normally I've seen a /64 as the subnet mask

ipadm create-add -T static -a [myIPv6addr]/44 igb0/v6

and I found that an IPv6 default route has just been installed automatically in my inet6 routing table!

I tried using a /64 prefix, but the router'IPv6 address was still outside the subnet address range

sorry, my mistake, the route appeared because of a previous tentative to install it with "route -p add -inet6 default ..."

but with a /44 I was able to set the inet6 default route, and it looks like it works: I'm able to ping ipv6.google.com

warden: reading up a bit /44 sounds odd for an IPv6 allocation, the standard allocation for an organisation is a /48 which they would normally break up into /64 subnets

a /48 allocation gives 2^16 (65,536) subnets of /64 size

some features in IPv6 are designed for a /64 sized network (and in most cases there's not really a good reason to do anything different)

Here is the network block my assigned IPv6 address is within: search.arin.net/rdap/?query=2607%3A5300%3A60%3A78d0%3A%3A1

I deduced the /44 prefix from there, but my IPv6 knowledge is ehm, less than sub-optimal! :S

The /44 is the amount of address space allocated to OVH as a whole

If your ISP is allocating you a /128 that's... damn near criminal.

Most likely you got a /64.

Are the gateway and your assigned address w/in the same /64 block?

2607:5300:60:78d0:: would the the right length for a /64

nomad: if it's a VPS (likely because OVH is a cloud provider), a /128 to start off with would not be unreasonable.

nomad: actually, since my address is 2607:5300:60:78d0::1, a /64 prefix would not include the address of my assigned gateway, which is 2607:5300:0060:78ff:00ff:00ff:00ff:00ff. At least a /48 prefix would be needed, I guess

ah, hosting provider. I was thinking NSP

warden, I think you should contact them ask ask what the prefix is, pointing out the problem you're having.

Surely I’ll ask them, and I’ll post their reply. Thanks

there might be some stuff you can adapt from help.ovhcloud.com/csm/en-gb-vps-con…icle_view&sysparm_article=KB0047569

that has (for linux) configuring the IP, setting a route for the default gateway on the if, then setting the default route to the gateway addr.

which I think is a valid setup, but slightly weird (especially if you've not seen that sort of thing before)

ohh, I don't like that setup at all.

"here, force your computer to think it's on the same block as the gateway"

Off-subnet gateways are regretably common in down-market hosting providers

so, as I read it, you have to set up your host with the /128 prefix then force a default route to point to the gateway that's in another block.

I'm somewhat surprised that they would be common in IPv6 though

(makes sense, sort of, for constrained IPv4 environments)

I'd prefer they used the link-local for the gateway if they're going to play those games.

right

I'm glad I've never encountered that in any form anywhere.

I hope that continues to be the case for me.

might as well us PPP at that point.

and if they've allocated ::1 as the system IP I suspect internally they've allowed for the whole /64 to be used by that vps (or maybe customer) so why not just do something sensible

so far I've only ever seen that sort of hack on IPv4 where a subnet has been allocated on the end of a ppp tunnel for DSL type services (I've had a few instances of having a /29 allocated as a customer and the default route is down an un-numbered PPPoA or PPPoE link)

point-to-point makes *some* sense for not wasting IPv4 addresses.

but AIUI IPv6 intended for /64 to be the smallest allocated block so people wouldn't have to mess with this kind of garbage config.

/64 is generally the smallest recommended allocation for a subnet, I think the only exception that's sometimes made is for something that's only ever going to be a P2P link between routers (but even then the argument is but why not just use a /64 - you have enoguh of them)

with the standard /48 allocation you've got as many subnets (of /64) as a site with an IPv4 class B (/16) has addresses.

having default point at a link-local address for the gateway would make more sense than what OVH is doing.

(oh, sorry, nomad already said that)

Yeah I feel like IPv6 link locals were invented, basically, exactly for this haha