I don't need to forward any ports but seemingly because I share an IP with a billion people I get Captchas everywhere (Google, Cloudflare etc.). I was even blocked from accessing Reddit without an account at some point.
They now support IPv6 but only with dynamic address allocations so you don't get a lot of advantages from it.
The User Terminal issues a router advertisement (RA) and my gateway gives itself an address in that /64 via SLAAC in addition to assigning itself an address from the /56 prefix.
If not using prefix delegation each host's address is dependent on their SLAAC policy - if not preferring stable addresses (e.g: EUI64) then of course the public address will vary (be dynamic) when using temporary "privacy" addresses.
My gateway delegates /60 sub-prefixes of the /56 and bare-metal hosts then either delegates /62 or advertises /64s from the /60 to VMs, containers, network namespaces and so forth.
As someone else described, I have my gateway also delegate ULA prefixes by changing just the first two octets of the public delegated prefix to fddc (fd = ULA, dc = "data center :) but otherwise identical and likewise on the bare-metal hosts, etc.
ULA is used for internal services; ISP delegated prefix for anything that needs public access.
Multicast-DNS takes care of internal hostnames; everything is ${hostname}.local
There's a separate VLAN for legacy IPv4-only devices that does NAT64 using a ULA prefix.
DNS64/NAT64 for the laggards like github.com that can't grok 128 bit addresses :)
The only time I have problems with web services is when their DNS advertises an AAAA resource record but their firewall/load-balancers/servers are not configured to allow/listen on it.
Starlink recently updated their FAQ with more info on addressing: https://www.starlink.com/support/article/1192f3ef-2a17-31d9-...
As for static addresses, it says "a reservation system retains the ... IPv6 prefix even when the system is off or rebooted. However, relocating the Starlink or software updates may change these addresses."
I suspect in practice the IPv6 address will only change if you get moved to a different POP ground station. Some customers never get moved. I've been moved several times because I'm in NorCal and they keep switching me between Seattle and Los Angeles.
Here's some recent discussion of users reporting what they've observed about changing IPv6 addresses: https://www.reddit.com/r/Starlink/comments/1b6mr4c/how_stati...
Even for a changing prefix, if operating a DNS authoritative server for a domain, any changes to the prefix can be quickly and automatically updated in both forward (AAAA) and reverse (PTR) resource records provided the TTL for those records is appropriately short, and thus allow almost seamless inbound via FQDNs. I do this with a bind9 (hidden) master locally that notifies external slave servers operated by a highly available, anycast, DNS service.
Unless the service explicitly states that your subnet is your or yours alone you should assume it's dynamic.
If you start relying on the prefix not ever changing you might have a bad surprise.
And from experience, that kind of surprises always come when you least need them.
I’m asking, because I’m an advocate of having your gateway advertise a separate, stable ULA /64 in conjunction with the globally-routable dynamic /64.
This gives you a stable set of addressable LAN IPs, and you can usually ignore the dynamic globally routable IPs.
Granted this won’t work for everyone, but if dynamic global addresses are an issue, you should be requesting a plan that supports a static delegation from your ISP anyway.
As you wrote, internally, you can use ULA. But you cannot open access from outside, because your firewall rules will become invalid with prefix change. With classic IPv4 NAT, your internal addresses don't change, so your port forwarding works, even if the WAN address changes.
Together, with a single /64 -- which means no subnets for you -- you are getting worse deal than with IPv4. You shouldn't have to contact your ISP for a plan (for a premium, obviously), that allows you to segment your network or open access to specific devices. What's the use of direct connections -- the IPv6 promise -- when you cannot use them anyway?
In short, with limitations like these, you are getting a bad deal.
I'm using Mikrotik, which doesn't allow prefix-less addresses in firewall, but allows you to put hostnames into your rules (so it will ask DNS what the address is and once the ttl expires, it will ask again).
On some CPEs (I don't remember which), it allowed to enter mac addresses, so the forwarding would always work for specific device, with any GUA address.
But we have to remember, that all these solution are optional and brand-specific; there's a wide range of devices that do not have anything to solve this problem.
My solution for my home network was to write a script that periodically checks my IPv6 prefix and updates the firewall rules and DNS if it ever changes. It doesn't feel like a great way to do it but it seems to work.
I think the more elegant solution is to use static IP space for hosting services, but most of us home users aren’t used to that.
Its not like IPv6 /56 subnets are expansive. Just give each customer a full /56 net and you are done.
I proposed that you might be able to route the external router’s WAN to a ULA via NAT to save in complexity when the PD changes, but I agree that a static delegation would by far be the easiest. Us home hosters aren’t used to that even though it is technically against the license agreement more often than not.
The other Starlink hassle is the geocoding for user IPv4 addresses is wildly wrong. I'm in Grass Valley, CA near Sacramento but sites all think my IP is either in Seattle or Los Angeles, depending on the week. This makes streaming services a huge PITA, I have to jump through hoops to convince them I'm in the Sacramento TV market about once a month. IPv6 could help with this too, Starlink could give out more precisely geolocated addresses. Not sure they're doing it though, all I see are IPv4 addresses in the geocoding feed: https://geoip.starlinkisp.net/feed.csv
YTTV at least will prefer your phone's geolocation to the IP address, that's how I "check in" to my metro every couple of months.