3 ms·

[not OP, but hey…] There’s no need for DHCP with IPv6. Clients choose the last 64 bits of an address randomly. The address space is huge — zero probability of

[not OP, but hey…] There’s no need for DHCP with IPv6. Clients choose the last 64 bits of an address randomly. The address space is huge — zero probability of a duplicate address. The first 64 bits therefore identify the network. If your ISP routes a /60 to you then you get to split that into 16x /64s. That’s probably fine, but the IETF recommendation is to dish out a /56 to small sites and give them a /48 if they ask for it. ISPs usually have multiple /32s at their disposal. It’s not about number of available addresses or networks. The joy of IPv6 is the addresses are so wide you can bring back hierarchical addressing. No internal routing chicanery is needed. If your site has 64 buildings then a /56 lets you assign a /62 to each, with 4x VLANs in each building eg for printers, guest net, phones, lighting, admin, with even a subnet for each business function in the building.

selfhoster11 5y ago
Some way of automatically propagating that network prefix to anything connected to the network would be nice. Otherwise we're just stuck punching in IP addresses like barbarians.
- ATsch 5y ago
  Not sure what you mean, but there's definitely no need to type addresses anywhere. Router Advertisements propagate the subnet information (prefix, dns server, etc.) to clients in the network. Prefix delegation allows downstream routers to request subnets from upstream routers. MDNS lets network devices announce their services to the subnet.
- gorgoiler 5y ago
  RA: router advertisements. The good riddance part of IPv4 DHCP is the server maintained state. The broadcast-config thing is still there. RADVD is the standard Linux daemon for this.
somerandomqaguy 5y ago
> The address space is huge — zero probability of a duplicate address. Not necessarily, there could be a flawed SLAAC implementation where the programmer just hard coded the default address after getting the PD. Or other some such silliness. Yes it breaks spec. But there's enough devices out there that break the link local configuration spec that I would not be surprised one but if someone pushed out a broken implementation of SLAAC on a commercial product.
- gorgoiler 5y ago
  DAD at the other end kills bad actors like this fast. But if the implementation at both ends is broken…?

selfhoster11 5y ago

Some way of automatically propagating that network prefix to anything connected to the network would be nice. Otherwise we're just stuck punching in IP addresses like barbarians.

ATsch 5y ago
Not sure what you mean, but there's definitely no need to type addresses anywhere. Router Advertisements propagate the subnet information (prefix, dns server, etc.) to clients in the network. Prefix delegation allows downstream routers to request subnets from upstream routers. MDNS lets network devices announce their services to the subnet.
gorgoiler 5y ago
RA: router advertisements. The good riddance part of IPv4 DHCP is the server maintained state. The broadcast-config thing is still there. RADVD is the standard Linux daemon for this.

somerandomqaguy 5y ago

> The address space is huge — zero probability of a duplicate address. Not necessarily, there could be a flawed SLAAC implementation where the programmer just hard coded the default address after getting the PD. Or other some such silliness. Yes it breaks spec. But there's enough devices out there that break the link local configuration spec that I would not be surprised one but if someone pushed out a broken implementation of SLAAC on a commercial product.

gorgoiler 5y ago
DAD at the other end kills bad actors like this fast. But if the implementation at both ends is broken…?