Why wasn't the 127.0.0.x address not used when they were running out of IP addresses?

Why wasn't the 127.0.0.x address not used when they were running out of IP addresses?

Yes I know 127.0.0.1 is the local loop back address, as well as 127.0.0.2 and 127.254.254.254. But do you really need 16.5 million loop back addresses? Wouldn't it be more effective to just use 127.0.0.1 the local loop back address and let everything else in the range be routeable? IPv6 fixed the address space issue, but I would have thought 16.5 million address not used a good way to extend the IPv4 address space.

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MAC_Addy

I believe, now correct me if I'm wrong, but when it was created, they thought they'd never run out of IPv4 addresses. So they kept the entire range for loopback testing.

Also, 16.5 million addresses? It's 2^16 (16 host bits available), which = 65,536.

amcnow

MAC_Addy wrote: »

I believe, now correct me if I'm wrong, but when it was created, they thought they'd never run out of IPv4 addresses. So they kept the entire range for loopback testing.

Also, 16.5 million addresses? It's 2^16 (16 host bits available), which = 65,536.

Isn't local loop back part of the class A address range?

TechGromit

amcnow wrote: »

Isn't local loop back part of the class A address range?

It's between A and B, so technically it could be shifted over to either one if they wanted to use the space. It would make more sense to make it a class A address, that would give them 16.7 million address to utilize.

MAC_Addy wrote: »

I believe, now correct me if I'm wrong, but when it was created, they thought they'd never run out of IPv4 addresses. So they kept the entire range for loopback testing.

But my point was when they realized "oh crap" they were running out of address, why didn't they pick the low hanging fruit and use the 127.x.x.x address space.

TheFORCE

Because it would not solve any problems it would just postpone it. They want IPv6 on everything, thats the real problem solver, so why waste time and effort to reuse 127 range. Thats my understanding.

amcnow

Fair enough regarding the classification of the 127.x.x.x address space. As for using it to extend IPV4, I concur with TheFORCE. It would only delay the inevitable.

PCTechLinc

amcnow wrote: »

Isn't local loop back part of the class A address range?

It is "part" of the Class A range, just reserved for the loopback purpose. Class A addresses have to start with a binary 0, so the range is 00000000 to 01111111, which is 0-127.

This is just hearsay, but I heard a long time ago that they didn't repurpose this range because things were already done with NAT to put a band-aid on running out of public IP addresses. On top of the really slow adoption of IPv6, they just left it alone.

Devilsbane

PCTechLinc wrote: »

This is just hearsay, but I heard a long time ago that they didn't repurpose this range because things were already done with NAT to put a band-aid on running out of public IP addresses. On top of the really slow adoption of IPv6, they just left it alone.

Not only would it only be a bandaid, but can you imagine the amount of systems that would need to be reconfigured to allow for this? And inevitably some system doesn't get updated and then it can't connect with any of the new IPs. Plus the training involved with getting all of us informed of the change. It's a losing battle.