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One thing I like about IPv6 is the lack of CIDR so that every IPv6 address always has the same 48 bit site prefix and then 16 bits of subnets and than 64 bits o
by UltraSane 2y ago
One thing I like about IPv6 is the lack of CIDR so that every IPv6 address always has the same 48 bit site prefix and then 16 bits of subnets and than 64 bits of host. It is easy to remember the 48 bit prefix and then you can actually just sequentially number subnets and hosts if you want so an address can be prefix:1:1 if you want.
One thing I hate about it is that they used 64 bits for host which is just absurd. 32 bits or even 16 bits would have been plenty for a single broadcast domain.
- Dagger2 2y agoThe 64-bit host space is used by SEND to hold a cryptographic key as part of a method of securing neighbor discovery. 16 or 32 bits would be laughably inadequate for that. It's also used as a passive defence against IP scanning, making it significantly harder for worms to spread by brute-force scanning. I admit it does make the address space look a bit lop-sided, but taking bits away from the host side (where they're being used) and giving them to the network side (where we should already have enough space anyway) wouldn't be a sensible trade.
- UltraSane 2y agoThat is a clever hack made necessary by the lack of crypto as part of the IPv6 protocol like it should have been. If they were more ambitious they would have built something like the Locator/ID Separation Protocol (LISP) (RFC 6830) directly into IPv6 but used public keys as the ID.