3
countries
200
AS-paths walked
877
hop observations
62
transit ASes seen
4
flagged filterers
Top filterers
Transit ASes
ranked by filter_score × log(paths_through), so the
list elevates ASes with BOTH substantial path coverage AND a high
fraction of hops where our forged PTB went unhonoured. Filter score is
not_honored / (honored + not_honored) across all hops we
tested in that AS's ranges. Minimum 3 paths and 5% filter score to
appear here.
| AS | Holder | paths | honored | not_honored | filter % | countries (paths) |
|---|---|---|---|---|---|---|
| AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI | 55 | 1 | 99 | 99% | ita(37), slo(12), srb(6) |
| AS6939 | HURRICANE - Hurricane Electric LLC, US | 101 | 1 | 1 | 50% | ita(85), srb(11), slo(5) |
| AS20473 | AS-VULTR - The Constant Company, LLC, US | 3 | 0 | 3 | 100% | ita(3) |
| AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT | 5 | 8 | 7 | 46% | ita(5) |
Methodology & caveats. For every AS where Type 2
verdicts disagreed across our vantages, we walked the local-vantage
forward path hop-by-hop, sending a 1500-byte ICMPv6 Echo to each
hop, then a forged ICMPv6 PTB (MTU=1280) sourced from our vantage,
then another 1500-byte Echo. If the second Echo Reply arrived
fragmented or with a smaller payload, the hop honoured the PTB.
Otherwise it didn't.
This tests host-mode PTB acceptance (PTBs aimed at the hop itself). A router that honours PTBs to itself can still be filtering PTBs transiting through it -- so a high filter score is strong evidence of an issue, but a low filter score isn't proof of full PTB transparency. Many hops drop ICMPv6 Echo to themselves or rate-limit it via CoPP; those are recorded as
Local-vantage only at present (orchestrator host). Per-vantage walks via SSH from the remote vantage points are a planned follow-up; that will sharpen the picture by exposing transits that filter asymmetrically.
This tests host-mode PTB acceptance (PTBs aimed at the hop itself). A router that honours PTBs to itself can still be filtering PTBs transiting through it -- so a high filter score is strong evidence of an issue, but a low filter score isn't proof of full PTB transparency. Many hops drop ICMPv6 Echo to themselves or rate-limit it via CoPP; those are recorded as
no_response
and excluded from the score denominator. Anycast destinations are
skipped explicitly.
Local-vantage only at present (orchestrator host). Per-vantage walks via SSH from the remote vantage points are a planned follow-up; that will sharpen the picture by exposing transits that filter asymmetrically.
Source data: data/global/ptb_atlas.json ·
rolling history at data/global/ptb_atlas_history/
(last 30 days).
Built daily by scripts/28_global_ptb_atlas.py.