AS12778 - Mega MPI/PARFC 4890 ✓RPKI ✓ 1/1ASPA ✓

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AS overview

Test target: 2a02:d68:2:10::1 · via IPv6 Hitlist (responsive) · address space: mixed · prefixes announced: 1

prefix(es): 2a02:d68::/32

Targets & per-vantage-point probe results (9 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
2a02:d68:2:10::1hit??-??-??-??-??-??-??-
2a02:d68:2:10::2hitrefusedrefused-refusedrefused-refusedrefused-??refusedrefused-refusedrefusedrefusedrefused-
2a02:d68:2:12::1hitrefusedrefused-refusedrefused-refusedrefused-??-refusedrefused-refusedrefused-refusedrefused-
2a02:d68:2:4::12hit??-??-??-??-??-??-??-
2a02:d68:2:4::13hit??-??-??-??-??-??-??-
2a02:d68:2:5::1hitrefusedrefused-refusedrefused-refusedrefused-??-refusedrefused-refusedrefused-refusedrefused-
2a02:d68:2:7::1hitrefusedrefused-refusedrefused-refusedrefused-??-refusedrefused-refusedrefused-refusedrefused-
2a02:d68:2:9::1rtrrefusedrefused-refusedrefused-refusedrefused-??refusedrefused-refusedrefusedrefusedrefused
2a02:d68::1prbrefusedrefused-refusedrefused-refusedrefused-??-refusedrefused-refusedrefused-refusedrefused-

SIX peering

SIX member - open peering, peering member, since 2002-02-04. IPv6 LAN: 2001:7f8:46:0:1:0:1:2778. Locations: lj_ijs, lj_tpl.

  • rs1-lan1-ipv6 → 2001:7f8:46:0:1:0:1:2778 Established (loc: lj_tpl, since 2026-09-21)
  • rs1-lan1-ipv6 → 2001:7f8:46::1:2778 Established (loc: lj_ijs, since 2026-09-21)
  • rs2-lan1-ipv6 → 2001:7f8:46:0:1:0:1:2778 Established (loc: lj_tpl, since 2026-08-24)
  • rs2-lan1-ipv6 → 2001:7f8:46::1:2778 Established (loc: lj_ijs, since 2026-09-18)

Announces via SIX route servers: 9 prefix(es) - 2001:67c:2730::/48, 2a02:23d0::/32, 2a02:28b0::/32, 2a02:28b1::/32, 2a02:7000::/32, 2a02:d68::/32, 2a04:dd40::/32, 2a06:c180::/29 (+1 more)

RPKI & ASPA

1 of 1 prefix(es) covered by a valid ROA.

PrefixRPKI stateReasonCovering VRP(s)
2a02:d68::/32✓ validmatched VRP (correct origin, length within maxLength)AS12778 /32 maxLen 32 (ripe)

ASPA: this AS has published an ASPA record listing 4 upstream provider(s) that are authorized to propagate routes from it: AS174, AS3356, AS5511, AS44306. Routes from this AS that arrive via any other upstream are considered ASPA-invalid by validators that enforce ASPA.

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

At least one router inside AS12778's announced prefix replied during the random-target probe. Hop(s): 2a02:d68:2:4::1, 2a02:d68:2:9::1. 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::912a02:d68:2:10::1icmp6-echoinconclusive2026-09-23T10:35:19Z
berlin2a06:d1c1:10b::cccc2a02:d68:2:10::1icmp6-echohonored2026-09-23T10:35:18Z
duseldorf2a06:d1c1:10d::aaaa2a02:d68:2:10::1icmp6-echohonored2026-09-23T10:35:15Z
go6lab2a00:8642:42::752a02:d68:2:10::1icmp6-echohonored2026-09-23T10:35:42Z
karsolink2a12:d8c0:105a:9001::a1542a02:d68:2:10::1icmp6-echohonored2026-09-23T10:35:19Z
odin2607:fae0:a000::422a02:d68:2:10::1icmp6-echohonored2026-09-23T10:35:14Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42a02:d68:2:10::1icmp6-echohonored2026-09-23T10:35:18Z

Attempt log (belgrade):

  1. icmp6-echoinconclusive (reply 1460 B before PTB): no Echo Reply after PTB (probe 1500B)
  2. dns-tcpno_tcp: connect failed: timed out
  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: timed out
  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: timed out
  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-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 (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: timed out
  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: timed out
  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
belgradeinconclusiveno_tcpno_tcpno_tcp
berlinhonoredno_tcpno_tcpno_tcp
duseldorfhonoredno_tcpno_tcpno_tcp
go6labhonoredno_tcpno_tcpno_tcp
karsolinkhonoredno_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): AS174, AS12778, AS3356.

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 AS12778

From SRB host (SOX, Belgrade)   open

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

4/4
Echo small (56B) 42.5ms
4/4
Echo 1500B (DF) 42.5ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a09:ab81::10.4ms0%*AS60733PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS
2sox-pn.sox.rs
2001:7f8:1e:8::3a
0.4ms0%AS13004SOX - Serbian Open Exchange DOO, RS
32001:7f8:1e:8::3d0.4ms0%AS13004SOX - Serbian Open Exchange DOO, RS
42001:67c:128c::69917.9ms0%-NA
5*-0%-
6*---
7*---
8*---
9*---
10*---
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---

tracepath -6

 1?: [LOCALHOST]                        0.011ms pmtu 1500
 1:  _gateway                                              0.494ms 
 1:  _gateway                                              0.300ms 
 2:  sox-pn.sox.rs                                         0.829ms 
 3:  2001:7f8:1e:8::3d                                     0.544ms asymm  2 
 4:  2001:67c:128c::699                                   19.607ms 
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From DE host (Berlin)   openRFC 4890 ✓

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

4/4
Echo small (56B) 32.7ms
4/4
Echo 1500B (DF) 32.2ms
no
Type 1 dest-unreach
-
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
0.6ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3ae0-150.cr10.fra01.lwlcom.net
2a00:c380:b200:230::174
9.9ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-20.cr10.fra07.lwlcom.net
2a00:c380:b200:230::31
10.1ms0%AS50629LWLCOM - LWLcom GmbH, DE
5*-70%-
6lo0.0.bar1.Ljubljana1.level3.net
2001:4c08::53
31.8ms0%AS3356LEVEL3 - Level 3 Parent, LLC, US
72001:1900:5:2:2::259a31.8ms0%AS3356LEVEL3 - Level 3 Parent, LLC, US
82a02:d68:2:4::131.8ms0%AS12778SGN - MEGA M, d.o.o., SI
9lj7.netsi.net
2a02:d68:3:1::231
32.2ms0%AS12778SGN - MEGA M, d.o.o., SI
10*-0%-
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---

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

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.447ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.452ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        3.504ms 
 3:  ae0-150.cr10.fra01.lwlcom.net                        10.163ms asymm  7 
 4:  ae0-20.cr10.fra07.lwlcom.net                         10.143ms asymm  6 
 5:  no reply
 6:  lo0.0.bar1.Ljubljana1.level3.net                     35.662ms asymm  7 
 7:  2001:1900:5:2:2::259a                                32.295ms asymm  8 
 8:  2a02:d68:2:4::1                                      32.082ms asymm  9 
 9:  lj7.netsi.net                                        32.972ms asymm 10 
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From DE host (Düsseldorf)   openRFC 4890 ✓

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

4/4
Echo small (56B) 26.9ms
4/4
Echo 1500B (DF) 27.5ms
no
Type 1 dest-unreach
-
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
0.1ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
0.9ms0%AS24961MYLOC-AS - WIIT AG, DE
3lag13.agr3-dus3.bb.wiit.network
2001:4ba0:ffe9:7d::1
5.6ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
0.2ms0%AS24961MYLOC-AS - WIIT AG, DE
5*-0%-
6lo0.0.bar1.Ljubljana1.level3.net
2001:4c08::53
26.5ms0%AS3356LEVEL3 - Level 3 Parent, LLC, US
72001:1900:5:2:2::259a26.1ms0%AS3356LEVEL3 - Level 3 Parent, LLC, US
82a02:d68:2:4::126.0ms0%AS12778SGN - MEGA M, d.o.o., SI
9lj7.netsi.net
2a02:d68:3:1::231
26.4ms0%AS12778SGN - MEGA M, d.o.o., SI
10*-0%-
11*---
12*---
13*---
14*---
15*---
16*---
17*---
18*---

tracepath -6

 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.426ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.344ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.543ms 
 3:  no reply
 4:  lag30.core3-dus1.bb.wiit.network                      0.343ms 
 5:  no reply
 6:  lo0.0.bar1.Ljubljana1.level3.net                     26.207ms 
 7:  2001:1900:5:2:2::259a                                26.233ms 
 8:  2a02:d68:2:4::1                                      26.428ms 
 9:  lj7.netsi.net                                        26.635ms 
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From NL host (go6lab)   openRFC 4890 ✓

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

4/4
Echo small (56B) 155.2ms
4/4
Echo 1500B (DF) 33.6ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::23.4ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2*-0%*-
32a00:1ca8:1::1944.3ms0%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:413.9ms0%AS50673Serverius-as - Serverius Holding B.V., NL
52001:978:2:40::3:13.3ms0%AS174COGENT-174 - Cogent Communications, LLC, US
6be3457.ccr41.ams03.atlas.cogentco.com
2001:550:0:1000::8275:109
6.6ms0%AS174COGENT-174 - Cogent Communications, LLC, US
7be2950.ccr42.fra05.atlas.cogentco.com
2001:550:0:1000::9a36:482a
14.5ms0%AS174COGENT-174 - Cogent Communications, LLC, US
8be7944.ccr22.muc03.atlas.cogentco.com
2001:550:0:1000::9a36:4b61
18.8ms0%AS174COGENT-174 - Cogent Communications, LLC, US
9be5456.ccr81.vie01.atlas.cogentco.com
2001:550:0:1000::9a36:48a6
22.3ms0%AS174COGENT-174 - Cogent Communications, LLC, US
10be4080.agr62.vie01.atlas.cogentco.com
2001:550:0:1000::8275:3252
23.3ms0%AS174COGENT-174 - Cogent Communications, LLC, US
11be9461.rcr62.lju01.atlas.cogentco.com
2001:550:0:1000::9a36:48a2
27.7ms0%AS174COGENT-174 - Cogent Communications, LLC, US
12be3191.nr61.b021176-0.lju01.atlas.cogentco.com
2001:550:0:1000::9a19:e7a
30.3ms0%AS174COGENT-174 - Cogent Communications, LLC, US
13*-0%-
14*---
15*---
16*---
17*---
18*---

tracepath -6

 1?: [LOCALHOST]                        0.045ms pmtu 1500
 1:  2a00:8642:42::2                                       2.272ms 
 1:  2a00:8642:42::2                                       3.026ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      9.109ms 
 4:  2a03:3f40::10:41                                      3.624ms 
 5:  2001:978:2:40::3:1                                    5.004ms 
 6:  be3458.ccr42.ams03.atlas.cogentco.com                 6.448ms 
 7:  be3343.ccr41.fra05.atlas.cogentco.com                14.858ms 
 8:  be5516.ccr21.muc03.atlas.cogentco.com                18.068ms 
 9:  be5456.ccr81.vie01.atlas.cogentco.com                25.544ms 
10:  be4079.agr61.vie01.atlas.cogentco.com                23.070ms 
11:  be9461.rcr62.lju01.atlas.cogentco.com                29.820ms 
12:  be3191.nr61.b021176-0.lju01.atlas.cogentco.com       30.477ms 
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From ITA host (Karsolink)   openRFC 4890 ✓

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

4/4
Echo small (56B) 35.5ms
4/4
Echo 1500B (DF) 43.2ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
2*-0%*-
3*-80%-
42a02:2d8:1:b80d:232a7.7ms0%-
5RT.IRX.VIE.AT.retn.net
2a02:2d8::57f5:e0af
11.3ms0%AS9002RETN-AS - RETN Limited, GB
62001:978:2:2a::e7:110.6ms0%AS174COGENT-174 - Cogent Communications, LLC, US
7*-0%-
82a02:d68:2:4::121.6ms60%AS12778SGN - MEGA M, d.o.o., SI
9be5892.ccr22.muc03.atlas.cogentco.com
2001:550:0:1000::9a36:3eda
19.3ms0%AS174COGENT-174 - Cogent Communications, LLC, US
10be5456.ccr81.vie01.atlas.cogentco.com
2001:550:0:1000::9a36:48a6
26.2ms0%AS174COGENT-174 - Cogent Communications, LLC, US
11*-0%-
12*-0%-
13be3191.nr61.b021176-0.lju01.atlas.cogentco.com
2001:550:0:1000::9a19:e7a
31.7ms0%AS174COGENT-174 - Cogent Communications, LLC, US
14*-0%-
15*---
16*---
17*---
18*---

Rate-limited ICMPv6: hop 3, hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.061ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.835ms 
 2:  2a12:d8c0:109f:121::a1                                0.656ms 
 3:  2a12:d8c0:101f:6::1                                   9.923ms 
 4:  2a03:b020:1:51::a                                    10.386ms 
 5:  rt.irx.mrs.fr.retn.net                               14.768ms 
 6:  2001:978:2:2a::e7:1                                  11.001ms 
 7:  no reply
 8:  2a02:d68:2:4::1                                      22.007ms asymm  9 
 9:  lj7.netsi.net                                        22.502ms asymm 10 
10:  no reply
11:  no reply
12:  be3189.rcr61.lju01.atlas.cogentco.com                31.759ms 
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From SLO host (6connect)   openRFC 4890 ✓

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

4/4
Echo small (56B) 1.7ms
4/4
Echo 1500B (DF) 1.8ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1fw1-lju.6connect.com
2607:fae0:a000::2
0.4ms0%*AS80386CONNECT - 6connect, Inc., US
2*-0%*-
32a03:a100:0:201:1::10.7ms90%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
4*-0%-
5*---
6*---
7*---
8*---
9*---
10*---
11*---
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19*---

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

tracepath -6

 1?: [LOCALHOST]                        0.032ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.754ms 
 1:  fw1-lju.6connect.com                                  0.522ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    1.072ms 
 3:  2a03:a100:0:201:1::1                                  1.129ms 
 4:  2a03:a100:0:201:1::1                                  1.452ms pmtu 1500
 4:  no reply
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
19:  no reply
     Too many hops: pmtu 1500

From SLO host (T-2)   openRFC 4890 ✓

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

4/4
Echo small (56B) 15.1ms
4/4
Echo 1500B (DF) 3.3ms
no
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
22a01:260:1::2251.8ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9a.core6.t-2.net
2a01:260:1:1::9a
2.6ms0%*AS34779T-2-AS - T-2, d.o.o., SI
42001:7f8:46:0:1:0:1:2778 @SIX3.4ms0%AS51988ARNES-SIX - ARNES, SI
52a02:d68:2:4::13.4ms-AS12778SGN - MEGA M, d.o.o., SI
6lj7.netsi.net
2a02:d68:3:1::231
3.8ms-AS12778SGN - MEGA M, d.o.o., SI
7*---
8*---
9*---
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18*---

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       2.893ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        2.539ms 
 4:  no reply
 5:  2a02:d68:2:4::1                                       3.949ms 
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
15:  no reply
16:  no reply
17:  no reply
18:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500