An Afternoon with ARIN

I had the opportunity to attend an ARIN on the Road event last week. It was an all-day event that focused on education: who ARIN is, what they do, and some things they are working on. As a network admin I’ve had to work with ARIN a handful of times to request network resources. I figured it would be a good experience to attend one of these events and see what ARIN has to say. I actually found out about a few things I wasn’t aware of previously, so this post is going to be a brief summary of what I learned.

About ARIN

If you haven’t already worked with them – ARIN is the American Registry for Internet Numbers ( They are a non-profit organization and their purpose is to assign/manage Internet number resources for all of North America. This includes IPv4/IPv6 addresses and BGP Autonomous System Numbers (ASNs). ARIN is one of five Regional Internet Registries (RIRs) – each managing Internet resources for it’s own individual region. All of these report back to a top-level organization, the Internet Assigned Numbers Authority (IANA).

What I didn’t know: ARIN actually used to manage resources for all of South America and Africa as well. LACNIC formed and took ownership of South America in 2001, and AFRINIC took Africa in late 2004. ARIN itself has only been around since 1997, and will be celebrating it’s 20th anniversary this December.

Outside of assigning/managing number resources – ARIN manages a huge manual of numbering policies and standards (The Number Resource Policy Manual). A good note here is that these policies are heavily influenced by the community – so if any individual or group of network operators want to change/modify or add new policies, then they can submit proposals to do so.

IPv4 Depletion

I was very interested to hear about what’s going on with IPv4/IPv6 – mostly because I’ve been trying to push for IPv6 in many of the places I have worked. The ARIN group spent a little bit of time talking about how the depletion of IPv4 addresses has affected their workload. Overall, it seems like their work has remained about the same – but it has transitioned from mostly IPv4 allocations to more IPv4 transfer requests.

An interesting note from this discussion was that ARIN only performs the backend registration changes for IPv4 block transfers. They play no part in the actual negotiations between two organizations. However, they do perform their own investigations during transfers to ensure that the source organization legitimately owns the IP block, and the destination organization can justify the use of the space.

I had heard previously that ARIN kept a block of IPv4 addresses for transition to IPv6 – but I never researched it further. This was a topic ARIN touched on during the event. Essentially, they have kept ownership of a /10 block of addresses, which is split up into individual /24 blocks for assignment. Any organization can request one of the /24s when they request a block of IPv6 addresses. The organization must fill out a justification form, in which they demonstrate how the IPv4 blocks will be used to help transition to IPv6. Organizations can request one of these blocks every 6 months, provided they can still justify the need for them. This is all documented in NRPM section 4.10.

The somewhat surprising thing here is that ARIN was actively encouraging people to take advantage of this. Probably because they need to push IPv6 adoption in any way they can. As of the date of the event, ARIN stated that only ~60 /24 blocks had been assigned so far.

IPv6 Adoption

This part of the event wasn’t quite everything I wanted it to be. Overall ARIN touched on statistics from Google and other organizations that show the trending uptake in IPv6 network access. They also spoke briefly about how the structure of IPv6 addresses makes life easier – because the last 64 bits can always be used for host-based MAC autoconfig, then network operators only worry about subnetting above that.

Interestingly enough, ARIN was advocating for the method of ‘assign way more addresses than you’ll ever need’ mentality for IPv6. Another attendee asked the question ‘Won’t we run into the same thing as IPv4, if we just throw out v6 blocks like candy’? This actually led to hearing something I wasn’t aware of – IANA has currently only made 1/8th of IPv6 blocks public available for use. The current numbering scheme/standard will be used for this first block of addresses. If we run through them too quickly, then we can step back and re-evaluate best practices before handing out the next 1/8th block of addresses.


Initially I was a bit confused that DNSSec was on the topic list – but I figured maybe ARIN was just trying to push this for the betterment of the Internet. While they spoke a bit about DNSSec for forward DNS, their primary topic was how DNSSec for reverse DNS isn’t something people are normally thinking about. As it turns out, ARIN offers reverse-lookup DNSSec for any IP blocks that they assign out. This is good to know, since reverse DNS can be important for things like email security – and its certainly something I’ve never really considered in the past.

If you have purchased IPv4/v6 blocks directly from ARIN – I would recommend that you check this out.


Resource Public Key Infrastructure (RPKI) is a way of cryptographically validating ownership of IP address space or routing objects. Since BGP is primarily a trust-based protocol between organizations, RPKI allows network operators to implement additional security by providing a certificate-based system of trust. The majority of this discussion was around how bad BGP security is, and that overall North America is far behind on implementing RPKI.

ARIN has a service available where they will act as your Certificate Authority (CA) for RPKI – so it only requires network operators to sign records then implement a few device changes.

My Thoughts

Overall the event was fairly informative! It wasn’t quite everything I wanted it to be, but I did walk away with additional knowledge that I didn’t have before. I was really hoping to learn more about how other organizations are implementing IPv6, or even how other people are convincing their employers to take IPv6 adoption seriously. When I spoke with some other attendees, it seemed like not many people had IPv6 running in a production environment yet – only a few of them had even started testing. Surprisingly, even the ARIN reps were repeatedly asking people to contact them if they had an IPv6 success story to share.

One thing I found really interesting was surrounding DNSSec/RPKI. A few attendees asked about how many people are actually validating signed resources. It’s one thing to implement signing, but it won’t matter if no one validates the resources, right? Surprisingly, ARIN had no statistics about this – and stated the point that they cannot enforce adoption of these standards. It certainly makes sense, but it’s not something I gave much thought to previously. Since they’re just a registry, they can only make these services available – not enforce their usage. This is why they put on events such as this to raise awareness and provide education.

ARIN pushed the fact that all of their policies are community driven. There were quite a few examples throughout the event of how individual members of the community could impact changes to their policies. My primary concern is that it seemed like a majority of the individuals in attendance represented government or educational organizations – and not a lot who worked in similar network environments to what I manage. They raised their own concerns and questions, which were certainly valid for the types of infrastructure and designs that they maintain. However, a number of these things don’t really apply to my infrastructure in quite the same ways.

If I have to make one point here: If you’re a network operator, go subscribe to ARINs mailing lists and get involved. Maybe you don’t have any ideas for policy changes, but you never know what might come up that you could provide meaningful input on. The ARIN reps provided an example or two of when a smaller group of people suggested policy changes which drastically affected bigger companies – and almost no one opposed it until it took effect. Only you have the ability to voice your opinion and concerns about how a proposed policy could affect your network. If not, the next time you try to request a block of IP addresses or a BGP ASN, you could potentially run into roadblocks because of a policy change proposed by someone with very different needs.

The staff at ARIN don’t live and work in the networks that we do. They try to work with network operators to understand use cases and the possible ramifications of policy changes – but ultimately they are a small non-profit. They can’t think of everything, nor can they force network operators to contribute their opinions. Get involved and make a difference.

As a final note, ARIN has a Fellowship Program where you can apply to attend one of their Public Policy meetings for free. Fill out an application and if you’re chosen they’ll provide a ticket, hotel room, and travel expenses. It’s a great opportunity to experience one of these meetings, especially if you might not have the financial means to otherwise.

The slide deck from the event is publicly available on ARIN’s website: here.