Will a single /27 get fully routed these days?

Sander Steffann sander at steffann.nl
Sun Jan 26 08:39:12 UTC 2014

Hi Owen,

>> Same question… Will people adjust their filters, (even if only for that prefix)? All over the world? I think 'will adjust their filters for XYZ' is highly optimistic, but let's hope it will work, otherwise the ISPs in the ARIN region will have a problem. (Or maybe not: existing ISPs (for who a /2[4-8] is not a significant amount) might not mind if a new competitors only gets a /2[5-8] that they cannot route globally. But I really hope it doesn't come to that.)
> Realistically, anyone depending on IPv4 is going to has a growing problem which will only continue to grow.

Yes, but those last IPv4 addresses are for ISPs who work with IPv6 and need a little bit of IPv4 to communicate with the legacy world. If they can't even do that it will be extra hard (impossible?) for them to function.

>> But more important: which /10 is set aside for this? It is not listed on https://www.arin.net/knowledge/ip_blocks.html
> I'm not sure it has been determined yet, let alone announced.

According to https://www.arin.net/resources/request/ipv4_countdown.html phase one it should have been done in September 2012: 'IPv4 address space required for NRPM 4.10, which sets aside a contiguous IPv4 /10 block to facilitate IPv6 deployment, was reserved and removed from the remaining IPv4 address pool.'  I can't find anything more specific though...

>>> Consider the possibility of a policy change which allows the transfer of smaller blocks (current ARIN policy limits this to /24 minimum, but ARIN policy is not immutable, we have a policy development process so that anyone who wants to can start the process of changing it.)
>> I’m well aware of that, but I’ll stick to RIPE policies for now :-)
> I admit I'm not familiar with the details of the RIPE policy in this regard. Do they allow longer prefixes to be transferred and/or acquired?

Allow: yes. Anybody doing that for globally routable purposes: no. Although it can be used for networks that don't need to be in the global BGP table.

> I will point out that the NA in NANOG mostly refers to the ARIN region.

??? No idea what this comment is supposed to mean. You may find this weird, but since the Internet is actually a global network I do care about what happens in NA...


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