AS208328 - L2N Luigi LabatePI/PARFC 4890 ✓RPKI ✓ 6/6ASPA -

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AS overview

Test target: 2a06:9f42::1 · static prefix probe · address space: mixed · prefixes announced: 6

prefix(es): 2a0a:6046::/32, 2a0a:6046:fe00::/40, 2a0d:b287:ee00::/40, 2a0d:b287:ec00::/40, 2a0a:6046:ff00::/40, 2a06:9f42::/32

Targets & per-vantage-point probe results (1 target(s) across 7 vantage point(s))

Source codes (hover any badge for full description): CUR=curated · NS/SOA/MX=DNS records · SPF=SPF TXT · DRV=holder-derived (www, ns1, mail, gw, …) · ATL=RIPE Atlas · PDB=PeeringDB · WHOIS=RIPE whois · RDAP=RIPE RDAP · HIT=IPv6 Hitlist · RTR=in-prefix path hop (router) · PRB=static prefix probe · SYN=synthetic prefix::1 fallback

Target IP / hostnameSourceSRB host (SOX, Belgrade)DE host (Berlin)DE host (Düsseldorf)NL host (go6lab)ITA host (Karsolink)SLO host (6connect)SLO host (T-2)
ping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reached
2a06:9f42::1prbrefusedrefusedrefusedrefusedrefusedrefused??refusedrefused-refusedrefusedrefusedrefused-

RPKI & ASPA

6 of 6 prefix(es) covered by a valid ROA.

PrefixRPKI stateReasonCovering VRP(s)
2a0a:6046::/32✓ validmatched VRP (correct origin, length within maxLength)AS208328 /32 maxLen 48 (ripe)
2a0a:6046:fe00::/40✓ validmatched VRP (correct origin, length within maxLength)AS208328 /32 maxLen 48 (ripe)
2a0d:b287:ee00::/40✓ validmatched VRP (correct origin, length within maxLength)AS208328 /40 maxLen 40 (ripe); AS41720 /29 maxLen 29 (ripe)
2a0d:b287:ec00::/40✓ validmatched VRP (correct origin, length within maxLength)AS208328 /40 maxLen 40 (ripe); AS41720 /29 maxLen 29 (ripe)
2a0a:6046:ff00::/40✓ validmatched VRP (correct origin, length within maxLength)AS208328 /32 maxLen 48 (ripe)
2a06:9f42::/32✓ validmatched VRP (correct origin, length within maxLength)AS208328 /32 maxLen 48 (ripe)

Random-IP probe (yarrp) into the AS' prefixes

At least one router inside AS208328's announced prefix replied during the random-target probe. Hop(s): 2a06:9f42::1, 2a0a:6046:ffe0::. These are candidate targets for direct testing.

ICMPv6 Type 2 (Packet Too Big) acceptance - active test

Vantage points disagree about Type 2 acceptance - transit ASes on one path may be filtering Type 2 even though the destination's stack accepts it on another path:

Why they disagree - measurement artifact: One vantage's probe didn't generate enough data to detect segment shrinkage (natural reply too small, or no second response). The other vantage's verdict is the meaningful one.

Failure detail - what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
belgrade2a09:ab81::912a06:9f42::1icmp6-echohonored2026-09-23T12:05:07Z
berlin2a06:d1c1:10b::cccc2a06:9f42::1icmp6-echohonored2026-09-23T12:05:03Z
duseldorf2a06:d1c1:10d::aaaa2a06:9f42::1icmp6-echohonored2026-09-23T12:05:02Z
go6lab2a00:8642:42::752a06:9f42::1icmp6-echohonored2026-09-23T12:06:14Z
karsolink2a12:d8c0:105a:9001::a1542a06:9f42::1icmp6-echoinconclusive2026-09-23T12:05:05Z
odin2607:fae0:a000::422a06:9f42::1icmp6-echohonored2026-09-23T12:05:03Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42a06:9f42::1icmp6-echohonored2026-09-23T12:05:06Z

Attempt log (belgrade):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (berlin):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (duseldorf):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (go6lab):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (karsolink):

  1. icmp6-echoinconclusive (reply 1460 B before PTB): no Echo Reply after PTB (probe 1500B)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (odin):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (t2):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpno_tcp: connect failed: [Errno 111] Connection refused
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

To match the corresponding ICMPv6 packet on your side (host firewall, AS edge, or transit tap), look for our PTBs around the timestamps above:

sudo tcpdump -i any -n -e 'icmp6 and ip6[40] = 2 and (src host 2607:fae0:a000::42 or src host 2a00:8642:42::75 or src host 2a01:261:313:b814:2a0:98ff:fe5b:13e4 or src host 2a06:d1c1:10b::cccc or src host 2a06:d1c1:10d::aaaa or src host 2a09:ab81::91 or src host 2a12:d8c0:105a:9001::a154)'

If you see our PTBs arriving but the destination's TCP/Echo flow does not shrink, the drop is in the destination kernel (cause 3 below). If you don't see them at all, drop is upstream of you (cause 2). If you only see them from some of our source IPs but not others, the drop is path-asymmetric - at least one transit on the differing route is filtering.

Where the path divergence is

Per-vantage probe + verdict (headline):

Full per-method matrix (all four methods run at each vantage):

vantageicmp6-echodns-tcptlshttp
belgradehonoredno_tcpno_tcpno_tcp
berlinhonoredno_tcpno_tcpno_tcp
duseldorfhonoredno_tcpno_tcpno_tcp
go6labhonoredno_tcpno_tcpno_tcp
karsolinkinconclusiveno_tcpno_tcpno_tcp
odinhonoredno_tcpno_tcpno_tcp
t2honoredno_tcpno_tcpno_tcp

✓ All vantages agree on method(s): icmp6-echo - the headline-method spread above is dispatcher noise, not a real Type 2 disagreement.

These vantage-level disagreements are rooted somewhere in the forward paths. Joining each per-vantage traceroute against the IP→AS lookup from our global yarrp mesh, the first hop where the paths land in different ASes is the most likely site of the offending filter / unreachable AS / Type 2 drop.

Suspect transit ASes (ranked by how often they appear at the divergence point on the path of the worse-classifying vantage): AS208328, AS6939, AS174.

Diagnosis is path-level, not packet-level: it tells you which transit AS is the prime suspect, not exactly which firewall rule is to blame. Use the tracepath6 output below (when available) for per-hop PMTU evidence on the same path.

Diagnostic interpretation

An operator-targeted diagnostic interpretation can be generated for this AS on demand. The pipeline holds the raw verdicts and the per-hop walk; an AI pass synthesises where to start looking. Click the button below to run it.

Multi-vantage path map

Every hop of all vantages’ traceroutes toward the target, drawn left→right, grouped into per-AS bubbles (a hop seen from several vantages is one shared bubble, so converging paths merge). It answers two questions per vantage — shown on each source bubble as echo ✓/⚠/✗ · trace ✓/✗: did the destination reply to ICMPv6 Echo (✓ honored, ⚠ replied but PTB not honored, ✗ no reply), and did the traceroute reach it. A line to the target is drawn only when that vantage got an echo reply — solid if the PTB was honored, dashed if not (reachable but a broken-PMTUD / RFC 4890 violation). The path depth still shows how far the traceroute itself got, and runs of unanswered (* *) hops collapse into one dashed “silent” bubble. Open full size ↗

multi-vantage path diagram for AS208328

From SRB host (SOX, Belgrade)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 45.0ms
4/4
Echo 1500B (DF) 44.9ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a09:ab81::10.3ms0%*AS60733PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS
2sox-pn.sox.rs
2001:7f8:1e:8::3a
0.2ms0%AS13004SOX - Serbian Open Exchange DOO, RS
32001:7f8:1e:8::3d0.4ms0%AS13004SOX - Serbian Open Exchange DOO, RS
42001:67c:128c::69917.7ms0%-NA
52a06:9f42::144.9ms0%AS208328L2N - Luigi Labate, IT

tracepath -6

 1?: [LOCALHOST]                        0.013ms pmtu 1500
 1:  _gateway                                              0.644ms 
 1:  _gateway                                              0.328ms 
 2:  sox-pn.sox.rs                                         0.452ms 
 3:  2001:7f8:1e:8::3d                                     0.609ms asymm  2 
 4:  2001:67c:128c::699                                   18.028ms 
 5:  2a06:9f42::1                                         45.053ms reached
     Resume: pmtu 1500 hops 5 back 7 

From DE host (Berlin)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 19.0ms
4/4
Echo 1500B (DF) 19.1ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1xe-0-0-13-178.gw01.ber01.as59645.net
2a06:d1c1:100:b::1
0.3ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2ae0-2453.cr10.ber01.lwlcom.net
2a06:d1c0::dead:beef:1c02
0.5ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3ae0-150.cr10.fra01.lwlcom.net
2a00:c380:b200:230::174
9.9ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-100.cr10.fra02.lwlcom.net
2a00:c380:b200:230::215
10.2ms0%AS50629LWLCOM - LWLcom GmbH, DE
5ffm-b29-link.ip.twelve99.net
2001:2035:0:2741::1
13.1ms0%AS1299TWELVE99 - Arelion Sweden AB, SE
62001:2034:a:3bc27.8ms0%-
72a06:9f42::119.2ms0%AS208328L2N - Luigi Labate, IT

tracepath -6

 1?: [LOCALHOST]                        0.019ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.527ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.486ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.871ms 
 3:  ae0-150.cr10.fra01.lwlcom.net                        10.252ms asymm  7 
 4:  ae0-100.cr10.fra02.lwlcom.net                        10.705ms asymm  8 
 5:  ffm-b29-link.ip.twelve99.net                         13.419ms asymm  9 
 6:  ffm-bb1-link.ip.twelve99.net                         27.948ms asymm  7 
 7:  2a06:9f42::1                                         19.556ms reached
     Resume: pmtu 1500 hops 7 back 8 

From DE host (Düsseldorf)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 13.4ms
4/4
Echo 1500B (DF) 13.4ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1xe-0-0-12-142.gw01.dus01.as59645.net
2a06:d1c1:100:d::1
0.2ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2ae0-101.cr10.dus02.lwlcom.net
2a06:d1c0::dead:beef:1301
6.1ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3ae0-20.cr10.dus01.lwlcom.net
2a00:c380:b200:230::108
0.5ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-90.cr11.dus01.lwlcom.net
2a00:c380:b200:230::222
0.7ms0%AS50629LWLCOM - LWLcom GmbH, DE
5ae0-30.cr10.dus06.lwlcom.net
2a00:c380:b200:230::36
1.0ms0%AS50629LWLCOM - LWLcom GmbH, DE
6ae1-20.cr10.fra05.lwlcom.net
2a00:c380:b200:230::245
4.5ms0%AS50629LWLCOM - LWLcom GmbH, DE
7ae0-10.cr10.fra02.lwlcom.net
2a00:c380:b200:230::237
4.7ms0%AS50629LWLCOM - LWLcom GmbH, DE
82001:2034:a:3bc21.8ms0%-
92001:2034:a:3bb21.8ms0%-
102a06:9f42::113.4ms0%AS208328L2N - Luigi Labate, IT

tracepath -6

 1?: [LOCALHOST]                        0.023ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.402ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.282ms 
 2:  ae0-101.cr10.dus02.lwlcom.net                         0.519ms 
 3:  ae0-40.cr10.dus05.lwlcom.net                          0.446ms 
 4:  ae0-70.cr10.fra04.lwlcom.net                          4.301ms 
 5:  ae0-30.cr10.dus06.lwlcom.net                          1.285ms 
 6:  ae0-40.cr10.fra06.lwlcom.net                          4.086ms 
 7:  ae0-10.cr10.fra02.lwlcom.net                          5.035ms 
 8:  ffm-b29-link.ip.twelve99.net                          6.925ms 
 9:  ffm-bb1-link.ip.twelve99.net                         22.710ms asymm  6 
10:  2a06:9f42::1                                         13.361ms reached
     Resume: pmtu 1500 hops 10 back 7 

From NL host (go6lab)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 28.8ms
4/4
Echo 1500B (DF) 27.5ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::21.9ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2*-0%*-
32a00:1ca8:1::1944.6ms10%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:416.5ms0%AS50673Serverius-as - Serverius Holding B.V., NL
52001:978:2:40::3:15.4ms0%AS174COGENT-174 - Cogent Communications, LLC, US
6be3457.ccr41.ams03.atlas.cogentco.com
2001:550:0:1000::8275:109
7.5ms0%AS174COGENT-174 - Cogent Communications, LLC, US
72001:978:3::ca7.6ms0%AS174COGENT-174 - Cogent Communications, LLC, US
82001:2034:a:775.5ms0%-
9*---
102a06:9f42::130.0ms0%AS208328L2N - Luigi Labate, IT

Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.034ms pmtu 1500
 1:  2a00:8642:42::2                                       1.961ms 
 1:  2a00:8642:42::2                                       2.253ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      3.861ms 
 4:  2a03:3f40::10:41                                      6.649ms 
 5:  2001:978:2:40::3:1                                    5.134ms 
 6:  be3458.ccr42.ams03.atlas.cogentco.com                 6.684ms 
 7:  2001:978:3::26                                        4.806ms asymm  6 
 8:  adm-bb2-link.ip.twelve99.net                          7.822ms asymm  7 
 9:  no reply
10:  2a06:9f42::1                                        639.607ms reached
     Resume: pmtu 1500 hops 10 back 11 

From ITA host (Karsolink)   open

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 8.5ms
3/4
Echo 1500B (DF) 8.6ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
2*---
32a12:d8c0:101f:6::19.7ms-AS204471KARSOLINK - 2S Computers SRL, IT
42a02:2d8:4:1815:232a3.6ms0%-
52a03:b020::2259.9ms0%AS41327FIBERTELECOM-AS - Fiber Telecom S.p.A., IT
6ffm-b14-link.ip.twelve99.net
2001:2035:0:2c32::1
22.7ms0%AS1299TWELVE99 - Arelion Sweden AB, SE
72001:2034:a:21a34.8ms0%-

tracepath -6

 1?: [LOCALHOST]                        0.023ms pmtu 1500
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                               71.870ms 
 3:  2a12:d8c0:109f:106::a2                                3.617ms 
 4:  ae8-202.RT.CLR.MIL.IT.retn.net                        8.308ms asymm  5 
 5:  2a03:b020::225                                       10.869ms 
 6:  ffm-b14-link.ip.twelve99.net                         20.096ms asymm  7 
 7:  2a06:9f42::1                                          8.904ms reached
     Resume: pmtu 1500 hops 7 back 7 

From SLO host (6connect)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 25.9ms
4/4
Echo 1500B (DF) 25.9ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1fw1-lju.6connect.com
2607:fae0:a000::2
0.3ms0%*AS80386CONNECT - 6connect, Inc., US
2ccr-to-fw-ccr1-gw-lju.6connect.com
2607:fae0:a000:2::2
0.6ms-AS80386CONNECT - 6connect, Inc., US
32a03:a100:0:201:1::10.8ms0%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
4e0-1.core1.lju1.he.net
2001:470:1:5be::1
2.0ms20%AS6939HURRICANE - Hurricane Electric LLC, US
5100ge0-0-0-5.core1.vie1.he.net
2001:470:0:578::1
9.1ms0%AS6939HURRICANE - Hurricane Electric LLC, US
6be3.core1.prg1.he.net
2001:470:e:a7::1
12.8ms0%AS6939HURRICANE - Hurricane Electric LLC, US
7be8.core4.fra1.he.net
2001:470:e:1e::1
18.5ms20%AS6939HURRICANE - Hurricane Electric LLC, US
8ffm-b14-link.ip.twelve99.net
2001:2035:0:26bf::1
18.8ms0%AS1299TWELVE99 - Arelion Sweden AB, SE
92001:2034:a:1e335.4ms0%-
102a06:9f42::125.8ms0%AS208328L2N - Luigi Labate, IT

Rate-limited ICMPv6: hop 4, hop 7 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.025ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.671ms 
 1:  fw1-lju.6connect.com                                  0.550ms 
 2:  no reply
 3:  2a03:a100:0:201:1::1                                  1.108ms 
 4:  2a03:a100:0:201:1::1                                  1.787ms pmtu 1500
 4:  no reply
 5:  100ge0-0-0-5.core1.vie1.he.net                        8.438ms 
 6:  be3.core1.prg1.he.net                                13.439ms 
 7:  be8.core4.fra1.he.net                                18.430ms 
 8:  ffm-b14-link.ip.twelve99.net                         20.725ms asymm 11 
 9:  ffm-bb2-link.ip.twelve99.net                         35.126ms asymm 13 
10:  2a06:9f42::1                                         26.700ms reached
     Resume: pmtu 1500 hops 10 back 13 

From SLO host (T-2)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

4/4
Echo small (56B) 75.7ms
4/4
Echo 1500B (DF) 50.2ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
22a01:260:1::2255.1ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9a.core6.t-2.net
2a01:260:1:1::9a
2.2ms0%*AS34779T-2-AS - T-2, d.o.o., SI
4hurricane-electric.nikhef.nlsix.net
2001:7f8:13::a500:6939:1
38.7ms0%*-NA
5hurricane-electric.nikhef.nlsix.net
2001:7f8:13::a500:6939:1
38.5ms0%-NA
6*---
7be47.core3.ams1.he.net
2001:470:e:12::2
37.9ms0%AS6939HURRICANE - Hurricane Electric LLC, US
8adm-b3-link.ip.twelve99.net
2001:2035:0:50b::1
34.7ms0%AS1299TWELVE99 - Arelion Sweden AB, SE
92001:2034:a:9529.1ms10%-
10prs-bb1-link.ip.twelve99.net
2001:2034:a:266::1
38.2ms0%AS1299TWELVE99 - Arelion Sweden AB, SE

Rate-limited ICMPv6: hop 9 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       4.457ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        2.897ms 
 4:  2a01-260-1-1--39.core6.t-2.net                        2.317ms asymm  3 
 5:  hurricane-electric.nikhef.nlsix.net                  41.940ms asymm  4 
 6:  be47.core3.ams1.he.net                               30.651ms 
 7:  adm-b3-link.ip.twelve99.net                          29.953ms asymm  5 
 8:  adm-b3-link.ip.twelve99.net                          35.433ms asymm  5 
 9:  adm-bb2-link.ip.twelve99.net                         32.480ms asymm  5 
10:  prs-bb1-link.ip.twelve99.net                         33.135ms asymm  5 
11:  2a06:9f42::1                                         41.186ms reached
     Resume: pmtu 1500 hops 11 back 7