Ask HN: List of Carrier-Grade-NATs (CGN/RFC1918) Used

3 points by dovholuknf 3y ago ↗ HN

I work on a zero trust overlay and we're having some debates about who uses what address space we should use, what others use etc. I know of a few solutions in the space using some ranges but I was wondering if there was a big long list of them somewhere of blocks known to be used.

I've been trying to "internet search" this but I've not found it yet. Any tips to find such a list, if it exists? Or just leave behind a comment on ones you know about - that'd help too. ;) TIA

3 comments

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QuarterRoy 3y ago ↗

They should always be just the 100.64.0.0/10 space - are you looking for specific ISP CGN allocations?

dovholuknf 3y ago ↗

Yeah. We use that address space too and currently we take up the whole /10. Some of us are like, "heck ya, all your ips belong to us" and some of us are like "hey, that's a lot of ips, how about we use a /16 instead" (for example)

So I'm trying to find all the current allocations out there. If there's such a list. Maybe I should make the list? :)

toast0 3y ago ↗

Realistically, get a BGP dump from someone (your network team or a public dump)... and someone is using all the large address blocks not advertised.

If you want your addresses not to conflict with anyone elses, you should get an IPv6 allocation and use that. Otherwise, you're simply going to have conflicts, the IPv4 address space isn't big enough.