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ASN & LIR
A practical walkthrough of ASN registration with RIPE — from picking uplinks to announcing your first routes.
An Autonomous System Number (ASN) is what lets your network speak BGP and announce its own IP prefixes to the internet. If you're multi-homed, peering with other providers, or planning to run your own IP space independently of a single upstream, you need one. Here's what the process actually involves.
An ASN is a unique number assigned by RIPE NCC that identifies your network on the internet and lets you run BGP sessions with other networks. Without it, your IP prefixes are tied to whichever provider announces them on your behalf — if you want to announce your own space, multihome across several providers, or do traffic engineering, an ASN is a prerequisite.
RIPE asks for a short technical justification and some supporting paperwork before it hands out a number:
An uplink is a network that agrees to carry your routes and run a BGP session with you. RIPE requires two of them to confirm your request before an ASN is issued. If you don't already have two providers lined up, we can help you find uplinks that are a good match for your location and traffic profile as part of our LIR services.
Once your two uplink confirmations and documents are in order, RIPE typically processes a complete ASN request within a few business days. Most of the time in practice goes into lining up uplinks and getting the paperwork right the first time — which is exactly what our ASN Registration & Support service is for.
With the ASN in hand, you register route and aut-num objects in the RIPE Database, set up RPKI (ROA) so your announcements validate, configure rDNS for your ranges, and establish BGP sessions with your uplinks. A minimal aut-num object in the RIPE DB looks like this:
aut-num: AS123456 as-name: EXAMPLE-AS org: ORG-EX1-RIPE admin-c: EX1-RIPE tech-c: EX1-RIPE status: ASSIGNED mnt-by: EXAMPLE-MNT source: RIPE
All of this lives in the RIPE Database, and you create and edit it through RIPE's own web interface: open Create an object, pick the object type from the dropdown — it lists every RPSL object type, from mntner and organisation down to things like route-set or rtr-set you'll rarely touch — fill in the attributes, and submit it signed by your maintainer. For an ASN setup, only a handful of those types matter, and they need to be created roughly in this order.
Create this first. A mntner (maintainer) is the authentication layer that protects every object you register afterwards — each one points back to it through a mnt-by attribute, and without the matching credentials nobody, including you, can edit them.
The organisation object ties every resource you hold — ASN, address space, domains — back to a single legal entity, and is what RIPE and your upstreams check when verifying who actually controls a resource.
Every object needs an admin-c and tech-c pointing at a contact. A person object represents one individual; a role object lets a whole team share one contact instead of registering each person separately — most operators use a role object for day-to-day administration.
RIPE creates the base aut-num object for you once the ASN is approved — you don't create it from scratch. What you do is open it for editing (search your ASN in the RIPE Database and choose update — the text-area edit mode is easiest for multi-line policy) and add the routing policy that tells the world which networks you accept and announce:
Before upstreams and RPKI validators will trust your announcements, every prefix you plan to announce needs a matching route (IPv4) or route6 (IPv6) object linking it to your ASN as the origin. Create one of each per prefix, logged in with the account tied to your maintainer.
If you, or your downstream customers, run more than one ASN, an as-set lets your upstreams build one filter that covers all of them instead of maintaining a separate one per BGP session.
Once the as-set exists, reference its name instead of a single ASN in your export lines, and give it to your upstreams so they can filter on it. We cover LOA, ROA, and rDNS setup as part of ASN Registration & Support, and can keep maintaining your mntner, organisation, route, and aut-num objects afterwards through our Object Support/Sponsorship service. See current ASN and LIR pricing or reach out at [email protected] if you'd like us to handle the registration for you.
