AS3212 - TelemachPI/PARFC 4890 ✓RPKI ✓ 4/4ASPA -

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AS overview

Test target: 2a00:13db:0:6::11 · ns1.telemach.net · address space: mixed · prefixes announced: 4

prefix(es): 2a00:fc0::/32, 2a05:acc0::/29, 2001:1688::/29, 2a00:13d8::/29

Targets & per-vantage-point probe results (10 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
2001:1688:fffc:11:101::1hit✓✓refusedrefused✓✓✓refusedrefused✓✓✓refusedrefused✓✓✓??✓✓✓refusedrefused✓✓✓refusedrefused✓✓✓refusedrefused-
2001:1688:fffc:11:101::2hit✗✗??-✗✗??-✗✗??-✗✗??-✗✗??-✗✗??-✗✗??-
2a00:13d9:100::1hit✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-
2a00:13d9:200::1hit✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-
2a00:13d9:300::1hit✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-
2a00:13d9:4e1::bhit✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-✓✓??-
2a00:13d9:520::ahit✓✓refusedrefused✓✓✓refusedrefused✓✓✓refusedrefused✓✓✓??✓✓✓refusedrefused✓✓✓refusedrefused✓✓✓refusedrefused✓
2a00:13db:0:6::11
ns1.telemach.net		drv✓✓??✓✓✓??✓✓✓??✓✓✓??✓✓✓??✓✓✓??✓✓✓??✓
2a00:13db:0:6::12
ns2.telemach.net		drv✓✓??✓✓✓??✓✓✓??✓✓✓??✓✓✓??✓✓✓??✓✓✓??✓
2a00:fc0:11:a000::16atl✓✓refusedrefused✓✓✓refusedrefused✓✓✓refusedrefused✓✓✓??✓✓✓refusedrefused✓✓✓refusedrefused✓✓✓refusedrefused✓

SIX peering

SIX member - open peering, peering member, since 2012-02-01. IPv6 LAN: 2001:7f8:46:0:1::3212. Locations: lj_ijs, lj_tpl.

  • rs1-lan1-ipv6 → 2001:7f8:46:0:1::3212 Established (loc: lj_tpl, since 2026-08-05)
  • rs1-lan1-ipv6 → 2001:7f8:46::3212 Established (loc: lj_ijs, since 2026-08-05)
  • rs2-lan1-ipv6 → 2001:7f8:46:0:1::3212 Established (loc: lj_tpl, since 2026-08-24)
  • rs2-lan1-ipv6 → 2001:7f8:46::3212 Established (loc: lj_ijs, since 2026-08-24)

Announces via SIX route servers: 28 prefix(es) - 2001:1688::/29, 2001:678:29c::/48, 2001:678:a88::/48, 2001:67c:179c::/48, 2001:67c:21f4::/48, 2001:67c:28f4::/48, 2001:67c:548::/48, 2604:ea80:6600::/40 (+20 more)

RPKI & ASPA

4 of 4 prefix(es) covered by a valid ROA.

PrefixRPKI stateReasonCovering VRP(s)
2a05:acc0::/29✓ validmatched VRP (correct origin, length within maxLength)AS3212 /29 maxLen 29 (ripe)
2001:1688::/29✓ validmatched VRP (correct origin, length within maxLength)AS3212 /29 maxLen 29 (ripe)
2a00:13d8::/29✓ validmatched VRP (correct origin, length within maxLength)AS3212 /29 maxLen 29 (ripe)
2a00:fc0::/32✓ validmatched VRP (correct origin, length within maxLength)AS3212 /32 maxLen 32 (ripe)

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

At least one router inside AS3212's announced prefix replied during the random-target probe. Hop(s): 2a00:fc0:10:306::b, 2a00:fc0:4314:b::a. These are candidate targets for direct testing.

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

Type 2 honored. Forged ICMPv6 PTB (MTU=1280) was accepted by the destination's stack: the next 1500-byte Echo Reply arrived split into 2 fragments via the IPv6 Fragment Header.
method: ICMPv6 Echo + forged PTB, tested 2026-09-23T10:33:30Z

tracepath6 per-hop PMTU drilldown

For each target where Type 2 verdicts disagreed across vantages, tracepath -6 ran from every vantage to capture per-hop PMTU evolution along that vantage's actual forward path. A pmtu change entry on a hop means that hop's router generated a PTB and we observed the shrink; absence of any change combined with a not_honored verdict suggests a router somewhere downstream is silently dropping >MTU packets (an RFC 4890 violation) rather than sending a PTB.

Target 2a00:13d9:100::1

amsterdam - verdict ?

(no hops captured)

belgrade - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22001:7f8:1e::121
32a03:dd80:1:1::1
42a03:dd80:2:e::1
52a00:fc0:3212:3::a
62a00:fc0:3212:200::a
72a00:fc0:2011::b
berlin - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:1c02
32a00:c380:b200:230::178
42a00:c380:b200:230::177
52001:7f8:30:0:2:1:0:3212
62a00:fc0:2011::b
duseldorf - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22001:4ba0:92f4:3::1
3<span class='muted'>no reply</span>
42001:4ba0:ffe9:109::2
52001:4ba0:ffe9:4f::1
62001:7f8::c8c:0:1
72a00:fc0:2011::b
go6lab - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a00:8642:1000:f000::1
32001:7f8:b7::a500:6939:1
42001:470:e:38::2
52001:470:e:1e::2
62001:470:e:a7::2
72001:470:1:bcc::2
82a00:fc0:2011::b
karsolink - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:101f:103::1
4<span class='muted'>no reply</span>
52001:470:0:414::1
62001:470:1:ab3::2
72a00:fc0:2011::b
odin - verdict honored

verdict = honored; final pmtu = 9000

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a03:a100:0:201:1::1
4<span class='muted'>no reply</span>
5<span class='muted'>no reply</span>
6<span class='muted'>no reply</span>
7<span class='muted'>no reply</span>
8<span class='muted'>no reply</span>
9<span class='muted'>no reply</span>
10<span class='muted'>no reply</span>
11<span class='muted'>no reply</span>
12<span class='muted'>no reply</span>
13<span class='muted'>no reply</span>
14<span class='muted'>no reply</span>
15<span class='muted'>no reply</span>
16<span class='muted'>no reply</span>
17<span class='muted'>no reply</span>
18<span class='muted'>no reply</span>
19<span class='muted'>no reply</span>
20<span class='muted'>no reply</span>
21<span class='muted'>no reply</span>
22<span class='muted'>no reply</span>
23<span class='muted'>no reply</span>
24<span class='muted'>no reply</span>
t2 - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9c
42001:7f8:46::3212
52a00:fc0:2011::b

Target 2a00:13d9:200::1

amsterdam - verdict ?

(no hops captured)

belgrade - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22001:7f8:1e::121
32a03:dd80:1:1::1
42a03:dd80:2:e::1
52a00:fc0:3212:1::a
62a00:fc0:2011:100::b
berlin - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:1c02
32a00:c380:b200:230::178
42a00:c380:b200:230::177
52001:7f8:30:0:2:1:0:3212
62a00:fc0:2011:100::a
72a00:fc0:2011:100::b
duseldorf - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22001:4ba0:92f4:3::1
3<span class='muted'>no reply</span>
42001:4ba0:ffe9:115::3
52001:4ba0:ffe9:4f::1
62001:7f8::c8c:0:1
72a00:fc0:2011:100::a
82a00:fc0:2011:100::b
go6lab - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a00:8642:1000:f000::1
32001:7f8:b7::a500:6939:1
42001:470:e:38::2
52001:470:e:1e::2
62001:470:e:a7::2
72001:470:1:ab3::2
82a00:fc0:2011:100::a
92a00:fc0:2011:100::b
karsolink - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:101f:103::1
4<span class='muted'>no reply</span>
52001:470:0:414::1
62001:470:1:ab3::2
72a00:fc0:2011:100::a
82a00:fc0:2011:100::b
odin - verdict honored

verdict = honored; final pmtu = 9000

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a03:a100:0:201:1::1
4<span class='muted'>no reply</span>
5<span class='muted'>no reply</span>
6<span class='muted'>no reply</span>
7<span class='muted'>no reply</span>
8<span class='muted'>no reply</span>
9<span class='muted'>no reply</span>
10<span class='muted'>no reply</span>
11<span class='muted'>no reply</span>
12<span class='muted'>no reply</span>
13<span class='muted'>no reply</span>
14<span class='muted'>no reply</span>
15<span class='muted'>no reply</span>
16<span class='muted'>no reply</span>
17<span class='muted'>no reply</span>
18<span class='muted'>no reply</span>
19<span class='muted'>no reply</span>
20<span class='muted'>no reply</span>
21<span class='muted'>no reply</span>
22<span class='muted'>no reply</span>
23<span class='muted'>no reply</span>
24<span class='muted'>no reply</span>
t2 - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9a
42001:7f8:46::3212
52a00:fc0:2011:100::a
62a00:fc0:2011:100::b

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 AS3212

From SRB host (SOX, Belgrade)   openRFC 4890 ✓

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

4/4
Echo small (56B) 14.4ms
4/4
Echo 1500B (DF) 14.5ms
yes
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
22001:7f8:1e::1211.9ms10%AS13004SOX - Serbian Open Exchange DOO, RS
32a03:dd80:1:1::11.0ms10%AS21215UGNI - UNITED GROUP NETWORK INFRASTRUCTURE d.o.o. Beograd, RS
4*-90%-
52a00:fc0:3212:1::a14.9ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI
6ns1.telemach.net
2a00:13db:0:6::11		13.1ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

Rate-limited ICMPv6: hop 2, hop 3, hop 4 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.011ms pmtu 1500
 1:  _gateway                                              0.447ms 
 1:  _gateway                                              0.429ms 
 2:  2001:7f8:1e::121                                      1.199ms 
 3:  2a03:dd80:1:1::1                                      1.405ms asymm  2 
 4:  2a03:dd80:2:e::1                                     14.020ms 
 5:  2a00:fc0:3212:1::a                                   15.622ms asymm  7 
 6:  ns1.telemach.net                                     13.419ms !A
     Resume: pmtu 1500

From DE host (Berlin)   openRFC 4890 ✓

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

4/4
Echo small (56B) 25.4ms
4/4
Echo 1500B (DF) 25.5ms
yes
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
3ae0-40.cr10.muc02.lwlcom.net
2a00:c380:b200:230::178		11.5ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-10.cr10.muc01.lwlcom.net
2a00:c380:b200:230::177		11.3ms0%AS50629LWLCOM - LWLcom GmbH, DE
52001:7f8:30:0:2:1:0:321220.9ms10%-NA
6*-70%-
7ns1.telemach.net
2a00:13db:0:6::11		26.7ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

Rate-limited ICMPv6: hop 5, hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.024ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.732ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.775ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        1.504ms 
 3:  ae0-40.cr10.muc02.lwlcom.net                         12.047ms 
 4:  ae0-10.cr10.muc01.lwlcom.net                         12.052ms 
 5:  2001:7f8:30:0:2:1:0:3212                             21.957ms asymm  7 
 6:  no reply
 7:  ns1.telemach.net                                     27.087ms !A
     Resume: pmtu 1500

From DE host (Düsseldorf)   openRFC 4890 ✓

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

4/4
Echo small (56B) 21.0ms
4/4
Echo 1500B (DF) 21.0ms
yes
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		0.2ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1		1.0ms0%AS24961MYLOC-AS - WIIT AG, DE
3lag13.agr3-dus3.bb.wiit.network
2001:4ba0:ffe9:7d::1		4.2ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag30.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:109::2		0.3ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag8.core1-dus-ix.bb.wiit.network
2001:4ba0:ffe9:8::2		0.4ms0%AS24961MYLOC-AS - WIIT AG, DE
62001:7f8::c8c:0:116.0ms0%-NA
7*-30%-
8ns1.telemach.net
2a00:13db:0:6::11		19.6ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

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

tracepath -6

 1?: [LOCALHOST]                        0.008ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.480ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.343ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.198ms 
 3:  no reply
 4:  lag30.core3-dus1.bb.wiit.network                      0.316ms 
 5:  lag8.core1-dus-ix.bb.wiit.network                     0.456ms 
 6:  2001:7f8::c8c:0:1                                    15.683ms 
 7:  no reply
 8:  ns1.telemach.net                                     19.846ms !A
     Resume: pmtu 1500

From NL host (go6lab)   openRFC 4890 ✓

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

4/4
Echo small (56B) 159.9ms
4/4
Echo 1500B (DF) 26.8ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::20.8ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2gw.friends.steffann.nl
2a00:8642:1000:f000::1		4.8ms0%*AS203993GNA-DC1-AS - S.J.M. Steffann, NL
3speed-ix.he.net
2001:7f8:b7::a500:6939:1		9.1ms0%-NA
4be2.core4.fra1.he.net
2001:470:e:38::2		12.5ms0%AS6939HURRICANE - Hurricane Electric LLC, US
5be8.core1.prg1.he.net
2001:470:e:1e::2		19.8ms0%AS6939HURRICANE - Hurricane Electric LLC, US
6be3.core1.vie1.he.net
2001:470:e:a7::2		22.9ms30%AS6939HURRICANE - Hurricane Electric LLC, US
7telemach-d-o-o.e0-66.core2.vie1.he.net
2001:470:1:ab3::2		20.5ms80%AS6939HURRICANE - Hurricane Electric LLC, US
82a00:13db:0:6::126.8ms30%AS3212TELEMACH - Telemach Slovenija d.o.o., SI
9ns1.telemach.net
2a00:13db:0:6::11		28.0ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

Rate-limited ICMPv6: hop 6, hop 7, hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.035ms pmtu 1500
 1:  ???                                                   2.850ms 
 1:  ???                                                   2.381ms 
 2:  no reply
 3:  speed-ix.he.net                                       6.585ms 
 4:  be2.core4.fra1.he.net                                11.318ms 
 5:  be8.core1.prg1.he.net                                17.434ms 
 6:  be3.core1.vie1.he.net                                23.659ms 
 7:  telemach-d-o-o.e0-66.core2.vie1.he.net               21.860ms asymm  8 
 8:  2a00:13db:0:6::1                                     31.079ms asymm 10 
 9:  ns1.telemach.net                                     28.474ms !A
     Resume: pmtu 1500

From ITA host (Karsolink)   openRFC 4890 ✓

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

4/4
Echo small (56B) 24.6ms
4/4
Echo 1500B (DF) 24.7ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
2*-0%*-
3*---
4*---
5100ge0-0-0-20.core1.vie1.he.net
2001:470:0:414::1		21.9ms40%AS6939HURRICANE - Hurricane Electric LLC, US
6telemach-d-o-o.e0-66.core2.vie1.he.net
2001:470:1:ab3::2		22.5ms0%AS6939HURRICANE - Hurricane Electric LLC, US
72a00:13db:0:6::126.6ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI
8ns1.telemach.net
2a00:13db:0:6::11		27.2ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

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

tracepath -6

 1?: [LOCALHOST]                        0.038ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        1.374ms 
 1:  karsolink-01.net.karsolink.com                        3.824ms 
 2:  2a12:d8c0:109f:121::a1                                1.320ms 
 3:  2a12:d8c0:101f:103::1                                 9.529ms 
 4:  no reply
 5:  100ge0-0-0-20.core1.vie1.he.net                      22.656ms 
 6:  telemach-d-o-o.e0-66.core2.vie1.he.net               22.151ms asymm  7 
 7:  2a00:13db:0:6::1                                     26.266ms asymm  9 
 8:  ns1.telemach.net                                     27.811ms !A
     Resume: pmtu 1500

From SLO host (6connect)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 9000

4/4
Echo small (56B) 1.2ms
4/4
Echo 1500B (DF) 1.1ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1fw1-lju.6connect.com
2607:fae0:a000::2		3.1ms0%*AS80386CONNECT - 6connect, Inc., US
2*-0%*-
32a03:a100:0:201:1::10.6ms10%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
42a00:fc0:4314:b::a2.0ms30%AS3212TELEMACH - Telemach Slovenija d.o.o., SI
5*-40%-
6ns1.telemach.net
2a00:13db:0:6::11		1.3ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

Rate-limited ICMPv6: hop 3, hop 4, hop 5 (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                                  0.655ms 
 1:  fw1-lju.6connect.com                                  0.881ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    0.736ms 
 3:  2a03:a100:0:201:1::1                                  0.909ms 
 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
     Too many hops: pmtu 9000
     Resume: pmtu 9000

From SLO host (T-2)   openRFC 4890 ✓

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

4/4
Echo small (56B) 2.5ms
4/4
Echo 1500B (DF) 3.3ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
22a01:260:1::22510.6ms0%*AS34779T-2-AS - T-2, d.o.o., SI
3*-0%*-
42001:7f8:46::3212 @SIX12.9ms0%AS51988ARNES-SIX - ARNES, SI
52a00:fc0:3212:1::a13.3ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI
6ns1.telemach.net
2a00:13db:0:6::11		10.4ms0%AS3212TELEMACH - Telemach Slovenija d.o.o., SI

tracepath -6

 1?: [LOCALHOST]                        0.025ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.951ms 
 2:  2a01:260:1::225                                       8.197ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.643ms 
 4:  no reply
 5:  no reply
 6:  ns1.telemach.net                                      3.735ms !A
     Resume: pmtu 1500