zlacker

On the other hand... What exactly is the benefit of IPv6 then? I thought the point was to make all my devices addressable on the public internet. How is it useful if the ISP firewall blocks my servers?

And yes, incompetent ISPs are the norm.

>>throwa+(OP)
The biggest benefit is exponentially higher complexity, assuring continued job growth for network engineers.

>>throwa+(OP)
The point is not needing a NAT translation table and running out of ports on your router. My provider also delivers an IPv6 configuration with all ports closed. I can enable incoming traffic for the devices that need it.

>>bzzzt+s9
Running out of ports how? Someone is hosting 65536 public services in their home network? Why not just pay for an additional public ipv4 then?

I can't configure anything technical about my internet. Any change is paid, and often simply not possible.

>>throwa+(OP)
Without bidirectional NAT, hole-punching works. Two sides of a p2p connection can coordinate with an intermediary to learn each other's addresses. They send each other a packet, which gets dropped by the other side. Their firewall sees the outgoing packet though, and opens the port. The next time they send each other packets, they will be allowed through. The intermediary is only needed to do the initial handshake instead of for all packets.

With NAT, it doesn't work because the ports get remapped, and the intermediary doesn't know how they will get remapped on the p2p connection, so they can't coordinate to send on the correct ports to open the firewall.

Or UPnP can work. By default, your router drops incoming packets on all ports. If you want to e.g. run a game server, then on startup, it hits a standard API to tell the router to forward that one port. On shutdown, it can tell it to close the port (you could potentially also have the router require keepalives to keep the forward alive. I'm not familiar with the details of UPnP and related protocols).

Without a public IP, you need intermediate servers to relay all traffic to you, which centralizes the web. With p2p working, you can e.g. have high quality video calls with friends/family instead of dealing with the garbage quality tech companies allow. Or I can share with my mom photos of her grandkids with effectively unlimited storage; for 2 years of 2 TB Google storage, I can buy 20 TB of disks.

>>throwa+Mb
Running out of ports is usually a misunderstanding, but a device doing stateful NAT will have a limit on how many states it can manage, and it's usually not fun when it goes over the limit.