AS3305 ISERE38

An autonomous system held by SFR (Société Française du Radiotéléphone), one

of France's major telecom operators. The registry handle ISERE38 points at the

Isère department (number 38) in south-eastern France.

What it's used for

• Registered to SFR, but currently announcing no IPv4 prefixes, so it carries no live traffic of its own today.
• The handle suggests a regional network for Isère that was folded into SFR; operators routinely retain such ASNs after absorbing regional or public- initiative networks.

Notable

• A registered but unannounced ASN is common in large carrier estates: numbers get inherited through acquisitions and kept on the books even when the network behind them has been renumbered into the parent's main ASN.
• Because nothing is routed here, this ASN will not appear as the origin of any traffic you see in the wild.

Interesting

• French departmental numbering leaking into an AS handle (38 for Isère) is a nice example of how much local context ends up encoded in registry names.