AS15733 — ZUMTOBEL-AS Corporate Datacenter Austria

AS15733 announces 1 IPv4 prefixes covering 65,536 addresses and 1 IPv6 prefixes.

About this network

Every sampled address answers with the same name, and the name is the word undefined.

What it's used for

• A lighting manufacturer's corporate network. One IPv4 /16 and one IPv6 prefix announced from Austria, sixty-five thousand addresses, through a single observed BGP neighbour.

Notable

• All three sampled addresses answer, and all three return undefined.zgrp.net, character for character the same.
• That domain is a four-letter contraction of the group name rather than the company's public one.
• The whole IPv4 holding is one /16, announced complete, with no smaller pieces.
• The AS handle continues past the abbreviation into a description naming a corporate data centre and the country.
• The single block's netname is the bare brand, and its only registrant is a hostmaster object. No company record and no abuse role are listed.
• Sixty-five thousand addresses depend on one upstream.

Interesting

• A reverse zone answering undefined for everything is a wildcard with a placeholder value. It was set so that every address returns something, and the something it returns is the word a program prints when it has no value to print.
• It is also useful in a way nobody intended. Three addresses spread across a /16 all answering identically says the zone is generated at the top and nothing below it is described.
• A manufacturer with a whole /16 and one upstream is an allocation from an era of plenty, routed as simply as it was in the year it arrived.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 146.108.0.0/16
• 2a03:39a0::/32

Upstream networks

• AS8447 A1 Telekom Austria AG

Adjacent networks

• AS8447 A1 Telekom Austria AG

Routing security

• RPKI: 0 valid, 0 invalid and 2 not-found announcements; 0 ROAs.
• ASPA: none published.
• IRR: 100% of announcements registered; 2 route objects.
• Listed in as-sets: AS-HURRICANEV6, AS-PTA, AS-TA6.