How are IPv6 addresses allocated?
How are IPv6 addresses allocated?
The issue here revolves around misunderstandings about firewall functionality. The explanation clarifies that firewalls, whether basic or advanced, primarily monitor incoming traffic and block unauthorized connections. It emphasizes that you don’t need to secure every device individually and highlights the importance of enabling ICMP for proper operation. The message aims to correct misconceptions and reassure customers about the practical aspects of firewall setup.
My assertions stem from my personal effort to implement IPv6 on my local network. I'm not claiming it's impossible, but I'm highlighting that as someone who has navigated IPv4 challenges, I've reached a significant obstacle with IPv6. The challenge lies not in capability, but in the complexity for everyday users. You're not alone in thinking it can be done, yet figuring it out feels like an insurmountable task. With IPv4, adding rules was straightforward; now, maintaining consistency across devices—like the XBox One that updates its unique ID each time—is a real hurdle. Plus, handling VPN users differently adds another layer of difficulty. The reality is, IPv6 demands a fundamentally different approach, especially without the traditional NAT support that eased adoption.
IPv6 supports DHCP similarly to IPv4, but offers more flexibility since you don’t always rely on it. The advantage lies in the fact that clients can operate without DHCP, and routers simply announce services. Whitelisting becomes straightforward by permitting certain ports as needed—just like IPv4 without NAT (or PAT). Problems with devices like Xbox usually stem from NAT, which isn’t present in IPv6. Sending traffic through a VPN has minimal impact; it mainly depends on routing methods. If precise control is required, DHCPv6 is the better choice. For most users, IPv6 simplifies things and reduces the need for complex configurations. In fact, many customer concerns revolve around NAT issues that are easily resolved by switching to IPv6. Don’t underestimate the importance of a solid DNS solution when managing these changes.
Companies should clearly state whether their routers include a built-in firewall to prevent external access. Without this protection, devices like my phone struggle, making hotspot connections uncomfortable. Knowing a reliable default setup would ease concerns about security behind the router.
I want to clarify aspects of your original inquiry that weren't fully addressed earlier. The main reason VPS providers allocate a /64 for each customer is due to email spam blacklists on IPv6 being set up to block entire ranges, not just specific ones like in IPv4. This means a single address can be affected if another user in the same provider’s network generates spam. Working with one provider I knew, they would group many customers into one /64, causing us to repeatedly get blocked by their own network for spam from other users. Splitting it helps prevent this issue—you shouldn’t be penalized because of another customer’s actions within the same VPS provider. Additionally, issues like Android developers refusing stateful DHCPv6 support led to the adoption of a new /64-per-host standard. Google supported this because they believed tethering was essential for many users, so they didn’t include full DHCPv6 client support. While some disagreed, the widespread use of Android made /64-per-host the standard we see today. Edited December 16, 2019 by Michael Ducharme
Imagine you only have a NAT setup without any firewall protection (using IPv4). This means anyone on the same public subnet can access your internal systems freely. For example, if you're connected to a cable modem and there are hundreds of other users on the same network, those users could reach your internal devices whenever they want.
NAT is designed to conceal several devices using one IP address. Public-facing devices would only detect your NAT gateway, even if someone connects directly to it. Your NAT needs instructions on how to route traffic. With ten devices behind a single NAT, it won’t automatically know where to send incoming data. That’s why we use DMZ to handle all traffic or set up specific port forwarding. If there’s just one device, it might forward all incoming connections to that point, functioning more like a bridge than a true NAT solution.
Picture Router 1 and Router 2 sharing the same public network. Assume Router 2 holds a LAN address at 192.168.1.1 with a full range of 255.255.255.0. The client on Router 1 initially sets up a static route for the 192.168.1.0/24 subnet, directing traffic through the WAN IP of Router 2. If Router 2 only employs NAT and lacks a firewall, incoming packets from Router 1 will be forwarded correctly to devices on its own subnet (Router 2 delivers them, handling the path from WAN to LAN). Router 1 would need to memorize or infer the exact subnet assigned by Router 2 and add the static route manually. This process could be streamlined automatically, allowing rapid testing of multiple IPs within the same subnet—especially common in typical home routers using 192.168.0.0/24 or 192.168.1.0/24 ranges. Even exhaustive scanning across all 192.168.x addresses would be simple, as most devices are configured on those networks.