non-private IPv4 addresses in LAN

[Justinh]

My company (very large, global) has been using a 134.x.x.x address range for intranet devices for like 15 years. (It just recently went to 10.x.x.x, so it made me think about this some more.)
How can a non-private address range be used in the LAN?

 

[ColinTaylor]

Well, just because you shouldn't disregard the agreed standards doesn't mean you can't. This is assuming that you don't actually own the 134.x.x.x address range, and want LAN devices to be directly accessible from the internet. At the end of the day there's nothing stopping you using whatever address range you want.

 

[tgl]

The thing that should stop you is that if you ever try to access external servers that legitimately live in 134.x.x.x, your network will misbehave and send you to local addresses instead. Of course, maybe that's what you want ... but it's the sort of thing that will bite you on the rear at unexpected times.

 

[Tech9]

servers that legitimately live in 134.x.x.x

This very large global company may be legitimately using this IP range.

 

[tgl]

Well, the question was quite vaguely worded ... but what I took it to mean is "what will happen if I just commandeer some public IP address range for my private network?"

 

[RMerlin]

My company (very large, global) has been using a 134.x.x.x address range for intranet devices for like 15 years. (It just recently went to 10.x.x.x, so it made me think about this some more.)
How can a non-private address range be used in the LAN?

This is how it used to work, NAT wasn't always a thing.

That's why in the early days, so many corporations jumped to grab a whole /8 even tho they definitely weren't going to run 16 millions servers within their business.

I've encountered one customer myself who used to do that. Me and our engineer were analyzing their network (a potential new customer at the time). Their rationale as to why it was this way? "We need that to provide remote access to some of our computers".

Yeaaahhhhh...

The scariest part is that potential customer was a governmental-related organisation.

 

[tgl]

Yeah, RFC1918 and the widespread adoption of NAT changed the landscape completely. Without that, IPv4 would've stopped being relevant at all years ago.

 

[Tech9]

but what I took it to mean is "what will happen if I just commandeer some public IP address range for my private network?"

I've read @Justinh question instead. It was pretty clear. The very large global company for sure owns some of the 134.x.x.x range, it's their decision how to use it and the answer is - the configuration is valid.