Why we have operated our own autonomous system since 2009

On the internet, networks are identified by an autonomous system (AS) number. Telefónica is AS3352. Level 3, AS3356. And elstir has been AS49008 since March 2009 — with our own /23 IPv4 block: 512 addresses registered in our name at RIPE, the European internet registry.

Why did a company our size get into that in 2009? For the same reason we keep maintaining it today: structural independence.

When your IP addresses belong to your transit provider — the operator that connects your network to the rest of the internet — changing provider means renumbering: changing DNS records, firewall rules, client VPNs, third-party whitelists. It’s the kind of silent dependency that doesn’t hurt until it hurts enormously. With our own AS and our own addressing, the IPs are ours wherever we go: the prefix is announced over BGP — the protocol the networks of the internet use to tell each other which routes exist — through whichever transit we choose, and if the route changed tomorrow, no client would have to touch a thing.

For our clients this translates into three concrete things. Stability: the IP of your mail server or your VPN hasn’t changed in years, and it isn’t going to. Our own reputation: our address space has a clean history that we control — and that matters, a great deal, for email deliverability. Continuity: infrastructure migrations happen underneath, without the addressing moving.

And like everything we say on this website, it can be checked: AS49008, its prefix and its history since 2009 are public on RIPE and bgp.tools. The full diagram of how it connects — from the big global carriers (tier-1 transit) to our clients’ systems — is on the infrastructure page.

Seventeen years on, there it is: same AS, same prefix, same addresses.