AS inventory
Austria has 640 autonomous systems visible in the global routing table. Of those, 612 (96 %) currently announce at least one IPv4 prefix to the global routing table, and 314 (49 %) currently announce at least one IPv6 prefix. That means 51 % of the IPv4-active ASes have followed through and turned on IPv6.
Operators - PA (Provider Aggregatable) holders
PA-holding ASes are LIRs with their own RIR allocation - they are the operators running parts of Austria’s internet (transits, ISPs, content networks with infrastructure of their own). Austria has 404 PA-holding operator ASes registered with the RIR. Of those, 394 (98 %) announce IPv4 today and 228 (56 %) announce IPv6.
End-sites - PI (Provider Independent) holders
PI-holding ASes hold address space directly from the RIR for their own use - typically enterprises, content sites running their own AS for routing diversity, government / academic single-site deployments. They’re not “operators” in the LIR sense, but they show up in BGP and their v6 readiness still matters. Austria has 193 PI-holding end-site ASes. Of those, 184 (95 %) announce IPv4 and 48 (25 %) announce IPv6.
Country totals: 640 routed ASes / 612 announce IPv4 / 314 announce IPv6. 40 ASes are unclassified (RIPE inet*num lookup didn’t return a clear status). PA / PI counts above include the “mixed” bucket on the PA side since a mixed AS holds at least one PA prefix and operationally functions as an LIR.
Executive summary
We measure how 314 Austrian autonomous systems that announce 970 IPv6 prefixes treat ICMPv6 in practice - Echo, Type 2 (Packet Too Big), Time-Exceeded - using eight ICMPv6 vantage points and a 12-node global yarrp mesh, plus the VIX route-server BGP table as ground truth. Generated 2026-09-22 14:21 UTC.
Adoption
According to RIPEstat, 314 ASes registered to Austria announce at least one IPv6 prefix to the global routing table, advertising 970 distinct prefixes between them. The 12-vantage-point mesh observed 303 distinct ASes (Austrian + foreign transits) and 572 AS-AS adjacencies along paths into Austria.
ICMPv6 behaviour at the destination
Each AS gets a single classification per vantage point by combining the small Echo, the an unfragmented 1500-byte Echo, traceroute reachability, and a TCP liveness check. Aggregated across all 8 vantage points, the AUT population looks like this:
- open - 156 ASes (50%)
- echo only - 5 ASes (2%)
- all blocked - 3 ASes (1%)
The open bucket means every vantage point received Echo Replies for both small and 1500-byte probes; this is what every AUT network should look like. echo_only means small ping passed but 1500-byte packets did not - usually either a path-MTU constraint downstream of us, or a real ICMPv6 Type 2 (Packet Too Big) filter en route. The two unreachable buckets cover ASes whose AS edge filters all incoming ICMPv6.
Weekly-probe schedule: 152 of AUT’s 314 IPv6-announcing ASes are on a weekly probe cycle today because they’ve produced a stably-unreachable / no-host result for 14+ consecutive daily runs. Today’s measurements therefore cover the 162 ASes probed this run; the skipped 152 are re-tested weekly. (Tuneable in scripts/19_update_skip_list.py -- raise STREAK_TO_SKIP to probe more aggressively, lower WEEKLY_PROBE_DAYS to re-test sooner.)
RFC 4890 compliance (active Type 2 test)
RFC 4890 gives operators the option to drop ICMPv6 Echo at the firewall, but says Type 2 (Packet Too Big) must remain permitted end-to-end - otherwise PMTUD is broken and large flows hang silently. We test this directly: for every reachable AS we open an active flow (TCP/53 DNS, TCP/443 TLS, ICMPv6 Echo, or HTTP/80 - whichever applies), forge an ICMPv6 Type 2 with MTU=1280, and observe whether the destination acts on it.
- RFC 4890 ✓ - 129 ASes proven compliant: AS1764, AS1853, AS1921, AS3330, AS5385, AS5404
- RFC 4890 ✗ - 30 ASes proven non-compliant (PMTUD will break for users): AS8787, AS15498, AS21013, AS28760, AS31382, AS34785, AS34883, AS35492
- The remaining 5 are unknown - typically because their network blocks Echo entirely (we cannot directly probe Type 2 acceptance from outside) or because the active test was inconclusive on this run.
Active-test method breakdown across all targets: honored = 2328, no_echo = 1244, not_honored = 669, inconclusive = 54, partial = 1.
VIX peering
The VIX (Vienna) currently has 173 peering members reachable via its route servers. Of those, 64 are Austrian-registered ASes; the rest are international peers that serve Austrian traffic via VIX (common examples: Hurricane Electric, Cloudflare, PCH).
Top VIX-internal transit relationships (BGP-truth)
For the full members list with live route-server session state, see the dedicated VIX page.
Path-MTU and Type 2 evidence
The active Type 2 test produced definitive verdicts for 213 unique destination IP addresses across vantage points.
- Honored (destination accepted our forged Packet-Too-Big and shrank its next response): 135 ASes - AS1764, AS1853, AS1921, AS3330, AS5385, AS5404, AS6798, AS8245 (+127 more)
- Not honored (destination ignored the PTB or the PTB was filtered en route): 78 ASes - AS1853, AS5385, AS5404, AS8339, AS8540, AS8787, AS12577, AS15498 (+70 more)
Global BGP visibility (RIPE RIS)
For every AUT prefix we asked all RIPE RIS collectors what AS-paths they currently see. That gives us each AS' direct upstream(s) according to the global BGP table.
RPKI & ASPA
RPKI ROAs cryptographically bind a prefix to its origin AS, so origin hijacks
of that prefix can be filtered. (Route leaks, where the origin is legitimate but the
AS path is not, are what ASPA below addresses.) We validate every announced AUT IPv6 prefix
against the local Routinator (rpki-lju.6connect.com).
Of 314 AUT ASes announcing IPv6:
- 237 (75%) have at least one valid ROA
- 218 (69%) have all their IPv6 prefixes covered by valid ROAs
- 77 (25%) have not signed any of their prefixes
- 0 have at least one invalid prefix (origin or maxLength mismatch)
Per prefix: 781 valid, 0 invalid, 189 not-found (of 970 total).
Top unsigned ASes (no ROAs)
- AS1205 University Linz (1 prefix)
- AS2494 IDDQD-AS (1 prefix)
- AS2604 MHS-GRAZ Graz University of Music and Performing Arts (1 prefix)
- AS8547 AS8547 Styria IT Solutions GmbH & Co KG (2 prefixes)
- AS8692 BRZ Bundesrechenzentrum GmbH (1 prefix)
- AS12401 INTERNIC-AS12401 internic Datenkommunikations GmbH (1 prefix)
- AS12991 Land-OOE Amt der Ooe. Landesregierung (1 prefix)
- AS13042 ASN-OENB-AT Oesterreichische Nationalbank (1 prefix)
- AS15498 RTCnow RTCnow Streaming Services GmbH (2 prefixes)
- AS15733 ZUMTOBEL-AS Zumtobel Group AG (1 prefix)
- AS21079 OEKB-AS Oesterreichische Kontrollbank Aktiengesellschaft (1 prefix)
- AS21360 Empirion Empirion Telekommunikations Services GmbH (1 prefix)
- AS21406 SWAROVSKI-AS DSW Kristall AG & Co KG (2 prefixes)
- AS24708 GRZ-AT RAITEC GmbH (1 prefix)
- AS24992 DIC-AS DIC Online Wolf Ltd & Co. KG (1 prefix)
ASPA (Autonomous System Provider Authorization)
ASPA is a much newer RPKI object (still an IETF SIDROPS draft, not yet a ratified RFC): it lets a customer AS list which upstream providers may legitimately propagate routes from it. Routes from that AS arriving via any other path are then ASPA-invalid.
27 of 314 AUT ASes have published an ASPA record:
- AS8412 TMA T-Mobile Austria GmbH - provider(s): AS3320, AS33891
- AS24824 WEISS-ASN Gebrueder-Weiss GmbH - provider(s): AS1299, AS3257, AS5385, AS8437, AS35280
- AS35492 Verein zur Foerderung freier Netze - provider(s): AS1121, AS1764, AS6939, AS47147, AS47692
- AS39210 CATV-AT T-Mobile Austria GmbH - provider(s): AS8412
- AS39878 RAUTER-AS Peter Rauter GmbH - provider(s): AS1299, AS3257, AS33891
- AS40994 Alwyzon Hohl IT e.U. - provider(s): AS174, AS1299, AS2914, AS3257, AS6762
- AS42729 Verein zur Foerderung freier Netze - provider(s): AS1113, AS35492, AS39837
- AS44765 MAKENEWMEDIA-AS MakeNewMedia Communications GmbH - provider(s): AS2914, AS6939, AS24953
- AS49432 SCHALLERT-AS Dominic Schallert trading as schallert.com e.U. - provider(s): AS48362, AS215510
- AS50920 KABEL-BRAUNAU Kabel Braunau GmbH - provider(s): AS28760, AS39878
- AS198603 SinovaTec Herbert Kaiser - provider(s): AS34872
- AS200273 kNET Lisa Lucia Kowalsky - provider(s): AS1764, AS29670, AS58299, AS216369
- AS200970 RIEPERT Riepert Informationstechnologie GmbH - provider(s): AS21013, AS33891, AS200683
- AS205163 OCTIGNITE Sergey Proshutinskiy - provider(s): AS835, AS6939, AS34927, AS41051, AS208453, AS212895
- AS206091 planet-digital Planet Digital Lichtwellenleiternetz Errichtungs- und Betrieb GmbH & Co KG - provider(s): AS31543
Path asymmetry
For every AUT AS we compared where our outgoing traffic enters their network (the AS just upstream of them on traceroute paths from any of our 8 ICMPv6 vantage points or the 12-node yarrp mesh, 20 sources in total) to which AS the global BGP table says is their direct upstream (RIS view). When these disagree, the network is usually multi-homed and traffic in and out takes different paths - normal in well-peered networks but worth surfacing.
116 AUT ASes flagged as asymmetric this run. Most asymmetric examples (low symmetry score):
- AS215136 Ryzehosting Finn Hess trading as Ryzehosting - symmetry score 0.00; RIS sees upstreams [AS207252, AS211066] but our paths went via [AS44592, AS49581].
- AS203358 INCOS-Stueckler Guenther Stueckler - symmetry score 0.00; RIS sees upstreams [AS60587] but our paths went via [AS5405, AS8540].
- AS25255 H3G-Austria-AS Hutchison Drei Austria GmbH - symmetry score 0.00; RIS sees upstreams [AS1764, AS3212, AS3303, AS5405] but our paths went via [AS6939].
- AS43771 MUKI-AS MuKi Versicherungsverein auf Gegenseitigkeit VVaG - symmetry score 0.00; RIS sees upstreams [AS33891, AS35369] but our paths went via [AS201011].
- AS41817 VFNK Rocket NG GmbH - symmetry score 0.00; RIS sees upstreams [AS59909] but our paths went via [AS1764, AS201011].
- AS64457 PIPEHOST-AS Matteo Fruhwald trading as PipeHost e.U. - symmetry score 0.00; RIS sees upstreams [AS6939, AS40994, AS51396, AS215120] but our paths went via [AS44592].
- AS216416 Evolus-Fibre Evolus IT Solutions GmbH - symmetry score 0.00; RIS sees upstreams [AS49581] but our paths went via [AS44592].
- AS204136 SILENT-GHOST-AS Kevin Holly - symmetry score 0.00; RIS sees upstreams [AS40994, AS50873] but our paths went via [AS24961].
Bottom line
- 50% of AUT IPv6 networks accept ICMPv6 Echo unrestricted from external probes.
- 1% of AUT IPv6 networks drop all ICMPv6 at their AS edge - a meaningful fraction of the AUT population that some traffic types may struggle to debug against.
- Of the 159 ASes where our active Type 2 test reached a verdict, 129 (81%) proved RFC 4890-compliant. The rest break PMTUD for any flow that needs a smaller path-MTU than 1500.
- The VIX route servers carry the BGP-truth backbone of Austrian IPv6: transit relationships visible on rs1 and rs2 today, with the country's largest ISPs dominating the inbound transit graph and a long tail of small ISPs and one-AS enterprises forming the customer base.
This report is regenerated daily at 12:00 Europe/Vienna from
data/analyzed.json, data/six_lg.json, data/global_topology.json,
data/ris_bgp.json, data/asymmetry.json and data/type2_results_<vantage>.json.
The text is deterministic - no manual editorial pass.