ASN Registration: Get It Right the First Time

By Savvas Bout, Founder of Prefixx. Last updated 21 September 2026.

Every BGP route announcement needs an origin AS, for example, registering your ASN at the beginning will save you lots of time troubleshooting later on. Starting the registration process early in the week, such as on monday, ensures you have time to address any documentation requirements before routing deadlines.

Preparing a BYOIP announcement or even taking over address space of acquired businesses, in all cases the ASN of the origin AS determines how your routing policies are interpreted over the internet. One misspelling with ARIN, RIPE NCC or APNIC can cause your block to not get announced over the internet for weeks while participants at the registry work on correcting the errors with the announcement.

Working closely with registry staff and following their guidance can help avoid such delays. Errors in origin AS configuration can introduce significant risk to your network's reachability and stability.

This guide describes the process in detail: the relevant registry services per region, the necessary documentation before application, processing time per registry and the steps after allocation of your ASN. It also explains special cases which might surprise engineers managing networks, such as how to request inter-RIR transfers of AS numbers. Following each step in sequence helps ensure a complete application that avoids common pitfalls during registry review.

Legacy resource holders may need assistance with the necessary documentation to create a link between their new ASN and a ROA as well as an IRR route object. If you are buying a block of IP addresses and also need an ASN, this guide also describes the options of brokerages as well as sponsoring-LIRs (Local Internet Registries) through Prefixx.

First we explain in advance what an ASN actually is and whether you need one. Brokerages and sponsoring-LIRs can help verify that all required details are correctly submitted to the registry before processing begins.

What is an autonomous system number and why registration matters

An Autonomous System Number (ASN) is a unique identifier assigned by a Regional Internet Registry (RIR) to an Autonomous System operating BGP. The ASN identifies the Autonomous System announcing the individual prefixes within the global routing table, thus enabling any person or routing entity worldwide to recognize that Autonomous System. Understanding this identifier requires foundational knowledge of how BGP routing protocols distinguish between different network operators. This identifier also facilitates the sharing of reachability information between autonomous systems across the internet.

What is an ASN and do I need one week of lead time?

An Autonomous System Number (ASN) is required when you want to announce your own IP space to one or more upstreams. Without an ASN you would be a dependent Annoucer and your IP space would be announced by your provider. Businesses that require routing independence, multi-homing or traffic engineering announcements require their own ASN. Organizations that manage their own ASN typically pay annual fees to their regional internet registry to maintain the resource allocation.

There are two formats available for registration of AS Numbers, with support for 16-bit ASNs (1 to 65535) and 32-bit ASNs (up to 4,294,967,295).

Each of the RIRs (ARIN, RIPE NCC, APNIC) has its own set of eligibility criteria to assign AS Numbers to connect to the routing community. Basically the main criterion is that a valid BGP plan with at least two neighbors has to be documented for registration.

Can Prefixx help me get an ASN alongside an IPv4 block purchase?

Our services can help source an ASN and set up the necessary block deals. We can also draft the LOA, RPKI ROA and IRR route objects required to get the routing up and running healthily. Please contact Prefixx.net to discuss your needs. Routing specialists at the firm can walk you through documentation requirements and registry procedures when you contact the team.

There are usually specific eligibility requirements for each domain name registry, and businesses or individuals applying for a domain name without the credentials to support it will have their application rejected, which will reset their time to apply for that domain name. Applicants must carefully fill out all required fields in the registry's application form to avoid such rejections.

Which organizations qualify in the ASN registration process

Not every organization can get a direct ASN registration. Each RIR has its own eligibility policy but they all require one thing: the applicant needs to have a need to exchange routing information with more than two networks or to have a serious multihoming case.

Eligibility by registry for cancellation requests

ASN registration fees and timeline at RIPE NCC or ARIN

Process times for such requests at the RIPE NCC for sponsored persons of LIRs can typically range from 5 to 10 working days, for ARIN similar times apply. Note that incomplete registration submissions typically mean the processing time will start all over again.

Please note that RIPE NCC updated the sponsoring-LIR fee structure in July and ARIN updated the RSA terms in September. Prefixx holds LIR status and can therefore sponsor a RIPE NCC ASN request, going through age-of-resource checks and enabling access to the RIPE databases. Some registries offer free ASN allocation under certain conditions, though sponsoring arrangements typically involve administrative fees for the LIR's services.

This leads to the task to put your IP space in order. An ASN without a routable IP prefix is useless. Before announcing routes, you must register your prefix allocations with the appropriate regional internet registry to establish ownership and maintain accurate WHOIS records.

How to complete IP address registration alongside your ASN

As previously submitted, an ASN by itself is useless. You also need to obtain IP space in order to start announcing routes via BGP. The process of obtaining IP space and the corresponding ASN is usually tied to your organization’s registration with a respective RIR. The RIR assignment process typically requires documentation of your network topology and intended use at each physical location.

Preparation: secure your IP addresses with the right support

1. Verify that you have a /24 or larger block of space to announce. Most BGP peers will not announce announcements smaller than a /24. Provider-independent (PI) space can be obtained from your RIR, or a suitable block can be sourced from a broker such as Prefixx.
2. Provider-assigned space is assigned by your upstream provider, whereas PI space is registered directly to you. This means you can take your PI space to any provider.

Can I register an ASN without becoming an LIR member?

RIPE NCC policies do allow for the assignment of an ASN and PI IP addresses to organizations that do not run their own local Internet registry. In such cases the sponsoring LIR will register the IP addresses on behalf of the organization. The sponsoring LIR ensures that all resources assigned under this arrangement remain properly documented in the RIPE database and comply with current policy requirements.

Link ASN to your address block via existing registration

1. Create IRR route objects. A route object needs to be registered in the IRR for every announced prefix in combination with the used ASN. Most upstreams require this for accepting announced prefixes.
2. Set up RPKI ROAs for your prefix. A ROA states that your ASN is allowed to originate a certain prefix. We can help you setting up ROAs for your prefixes via our member portal. RIPE NCC also offers training sessions in October and throughout the year to help you setup RPKI ROAs for your prefixes.
3. Announce and verify. Bring up your BGP session, announce the prefix and verify origin validation using RIPEstat.

Now that you have secured and linked your IP addresses, you can proceed through the formal registration process for each step in sequence.

How Prefixx supports ASN sourcing and routing setup

Prefixx is a boutique IPv4 brokerage founded in 2018, based in Miami. We source ASNs, negotiate block deals in advance, and setup all routing for you.

• ASN sourcing is also included in our brokerage services for ASN acquisitions, in conjunction with IP resources brokerage across ARIN, RIPE NCC, APNIC, and LACNIC registration services.
• RIPE LIR sponsorship for PI/ASN holders without their own local internet registry. We offer a sponsoring-LIR service for a fee of $300/year (plus a start fee of $300 per object).
• We manage the routing paperwork for you. We create the LOA, RPKI ROA and IRR route objects for you to announce BGP prefixes.
• BYOIP on bare metal. BYOIP deployment onto Netrouting bare metal is natively included with no per-IP surcharge. See Prefixx.net/BYOIP for details.

Our consultants are here to help with any questions you have regarding the ASN registration process, or assist in routing your own IP address space.

Note that although registration of an ASN is a technical step, the process is far more accessible than most people give it credit for. There are essentially two filters to this process: the ASN applicant must submit a sufficient online justification for multihoming/routing policy needs, and demonstrate eligibility as per the relevant RIR.

The other aspect that most applicants underestimate is the IP address side of the ASN. An ASN without a corresponding routable IP block is essentially useless. Registration of the IP addresses, transfer of the IP addresses, RPKI ROAs, IRR route objects and corresponding LOAs all need to be put in place in a correct order, otherwise the prefix will not propagate.

If you need an ASN sourced alongside a block, or you want a specialist to handle the routing paperwork from start to finish, Prefixx manages both. Reach out this September to discuss which services your network actually needs.