IPv4 is almost gone (in Europe anyway) • Hacker News Board

Re: IPv4 is almost gone (in Europe anyway)

#51

Post by agwa » Sat, Sep 15, 2012, 2:17 AM UTC

km3k wrote: post #49

diminoten wrote: post #47

Earlier quoted context omitted.

It truly is saddening how we're treating v6

I agree. It seems like we're setting up the IPv6 address space to be wasted.

Actually, there's a good reason why IPv6 subnets are so large - it's because with stateless auto configuration, the lower bits (the "Interface ID") of the address are derived from the MAC address, which is 48 bits.[1] (Stateless auto configuration is brilliant because, despite being stateless (unlike DHCP), no two devices will ever be assigned the same IP address on a subnet.) 48 Another way of looking at this is that IPv6 could have been just IPv4 with 64 bit addresses, and we would have been fine. However, the designers decided to add stateless auto configuration, and added another 64 bits to make it work.

[1] In privacy mode, the Interface ID is generated randomly instead of from the MAC address (to prevent tracking by MAC address). In this case, you still need lots of bits to make the probability of a collision insignificant.

Re: IPv4 is almost gone (in Europe anyway)

#52

Post by devdas » Tue, Sep 18, 2012, 5:13 PM UTC

_suoiruc wrote: post #43

I know these folks are well-meaning but I find these constant "warnings" to be insulting. What people really need to be aware of is that the folks making decisions of how the internet should run, "the experts", are not always as smart as they think they are. They make mistakes. And it's hard to get a bunch of know-it-all's to agree. It's also hard to get the entire `net to switch their behaviour, and adopt something…

What happens when your ISP has to NAT you?

Re: IPv4 is almost gone (in Europe anyway)

#53

Post by juan_juarez » Tue, Sep 18, 2012, 10:34 PM UTC

TazeTSchnitzel wrote: post #45

juan_juarez wrote: post #44

Earlier quoted context omitted.

> PHP still fails It still fails to reject February 31, I'm completely not surprised to hear that it fails on IPv6.

I don't know which specific function you're talking about, but there may be a good reason for it.

Both strtotime() - PHP's "take a string and do your damnedest to make a date out of it" function - and DateTime.parseFromFormat() - the more restrictive TZ-aware class - accept it and give you March 2/3. There's a separate validate_date() or something like that that actually rejects Feb 31.

Re: IPv4 is almost gone (in Europe anyway)

#54

Post by TazeTSchnitzel » Tue, Sep 18, 2012, 10:38 PM UTC

juan_juarez wrote: post #53

TazeTSchnitzel wrote: post #45

Earlier quoted context omitted.

I don't know which specific function you're talking about, but there may be a good reason for it.

Both strtotime() - PHP's "take a string and do your damnedest to make a date out of it" function - and DateTime.parseFromFormat() - the more restrictive TZ-aware class - accept it and give you March 2/3. There's a separate validate_date() or something like that that actually rejects Feb 31.

I'm not sure that's entirely wrong, just a different attitude than you might expect. Also, for that matter, I think MySQL accepts, will store, and will retrieve Feb 31 IIRC. Why? It's liberal in the correctness of input.