AS2597 - CCTLD-IT Consiglio Nazionale delle RicerchePI/PARFC 4890 ✓RPKI -ASPA -

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AS overview

Test target: 2a00:d40:1:1::5 · dns.nic.it · address space: mixed · prefixes announced: 11

prefix(es): 2a00:d40:109::/48, 2a00:d40:101::/48, 2a00:d40:108::/48, 2a00:d40:6::/48, 2a00:d40:107::/48, 2a00:d40:102::/48, 2a00:d40:2::/48, 2a00:d40:7::/48 (+3 more)

Targets & per-vantage-point probe results (5 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
2a00:d40:1:1:192:12:192:20
mail.nic.it
MXopenopenopenopenopenopenopenopenopenopenopenopenopenopen-
2a00:d40:1:1:192:12:192:40
nic.it
DMARCopenopenopenopenopenopenopenopenopenopenopenopenopenopen
2a00:d40:1:1::2
ns1.nic.it
whois??????????????
2a00:d40:1:1::3
ns2.nic.it
whois??????????????
2a00:d40:1:1::5
dns.nic.it
NSrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefusedrefused

MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO peering

MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO member - Selective peering, peering member, since 2012-03-27. IPv6 LAN: 2001:7f8:b:100:1d1:a5d0:2597:79. Locations: -.

RPKI & ASPA

0 of 11 prefix(es) covered by a valid ROA, 11 not-found.

PrefixRPKI stateReasonCovering VRP(s)
2a00:d40:109::/48- not-foundno covering VRP
2a00:d40:101::/48- not-foundno covering VRP
2a00:d40:108::/48- not-foundno covering VRP
2a00:d40:6::/48- not-foundno covering VRP
2a00:d40:107::/48- not-foundno covering VRP
2a00:d40:102::/48- not-foundno covering VRP
2a00:d40:2::/48- not-foundno covering VRP
2a00:d40:7::/48- not-foundno covering VRP
2a00:d40:100::/48- not-foundno covering VRP
2a00:d40:104::/48- not-foundno covering VRP
2a00:d40:1::/48- not-foundno covering VRP

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

We probed 70 arbitrary IPv6 address(es) inside AS2597's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:41a8:40:2::24a at hop 22 - that router answers ICMPv6 Echo. This is not in AS2597's announced prefix; operationally it's the AS-edge / peering interface (often on an IXP peering address or an upstream's /127 link). The traceroute boundary is the AS edge: ICMPv6 Time-Exceeded responses from anything inside this AS are filtered.

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 - path-asymmetric Type 2 filtering: Both vantages used the ICMPv6 Echo + forged-PTB method on the same destination IP, but reached different verdicts. The destination's stack is the same in both cases - so the difference is in the path: a transit AS on one route filters our forged Type 2 (or its return ICMPv6 carrying the embedded packet) while the other route delivers it intact. The vantage that says honored shows what the destination's stack actually does; the one that says not honored shows that the path between us and them drops Type 2.

Failure detail - what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
belgrade2a09:ab81::912a00:d40:1:1::5icmp6-echohonored2026-09-23T12:01:24Z
berlin2a06:d1c1:10b::cccc2a00:d40:1:1::5icmp6-echohonored2026-09-23T12:01:23Z
duseldorf2a06:d1c1:10d::aaaa2a00:d40:1:1::5icmp6-echonot_honored2026-09-23T12:01:22Z
go6lab2a00:8642:42::752a00:d40:1:1::5icmp6-echonot_honored2026-09-23T12:02:07Z
karsolink2a12:d8c0:105a:9001::a1542a00:d40:1:1::5icmp6-echohonored2026-09-23T12:01:21Z
odin2607:fae0:a000::422a00:d40:1:1::5icmp6-echohonored2026-09-23T12:01:19Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42a00:d40:1:1::5icmp6-echonot_honored2026-09-23T12:01:22Z

Attempt log (belgrade):

  1. icmp6-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (duseldorf):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (go6lab):

  1. icmp6-echonot_honored (reply shrank 1360→1360 B)
  2. dns-tcpinconclusive (reply 87 B before PTB): max DNS-over-TCP segment 87B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  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-tcpinconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrink
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (t2):

  1. icmp6-echonot_honored (reply shrank 1460→1460 B)
  2. dns-tcpinconclusive (reply 119 B before PTB): max DNS-over-TCP segment 119B; not big enough to test PMTU shrink
  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.

What does "Type 2 not honored" actually mean? - click to expand

What this test does

Using the icmp6-echo method, we send a 1500-byte ICMPv6 Echo Request, then a forged ICMPv6 Type 2 (Packet Too Big) declaring path MTU=1280, and observe whether the next Echo Reply arrives split into IPv6 fragments. RFC 4890 requires hosts and intermediate networks not to filter ICMPv6 Type 2; the destination's TCP/UDP stack must act on a received PTB by lowering its Path MTU cache for that destination, which makes subsequent segments smaller.

What we measured

The TCP segment size your server emitted before our forged Type 2 was 1460 B; after, it was 1460 B. No change. RFC 4890 ("Type 2 messages MUST NOT be filtered") expects subsequent segments to shrink to fit a Path MTU of 1280 B.

Three plausible causes

  1. Your host firewall is dropping ICMPv6 Type 2 inbound. Many default firewall rule sets only allow Echo Request/Reply and Neighbor Discovery, silently dropping all other ICMPv6 types - including Packet Too Big.
  2. An upstream / transit network is dropping ICMPv6 Type 2 before it reaches you. Some transit ASes filter ICMPv6 messages other than Echo at the edge. The forged PTB never arrives, so your stack never has a chance to act on it.
  3. Your kernel is ignoring the PTB. Linux / BSD stacks normally accept ICMPv6 PTB and update the route cache, but a few sysctls (or a hardened kernel) can be configured to ignore PMTU updates - typically as part of an over-aggressive anti-spoofing or uRPF policy.

How to check & fix (Linux examples)

1. Confirm Type 2 is not blocked at the host firewall:

sudo ip6tables -L INPUT -nv | grep -iE 'icmpv6|packet-too-big'
sudo nft list ruleset 2>/dev/null | grep -A1 'icmpv6'

If you see rules dropping ICMPv6 unconditionally, change them to permit at least icmpv6 type packet-too-big (and destination-unreachable, time-exceeded, parameter-problem per RFC 4890).

2. Confirm the kernel accepts incoming PTB:

sudo sysctl net.ipv6.conf.all.accept_redirects net.ipv4.ip_no_pmtu_disc net.ipv6.route.mtu_expires

The defaults (accept_redirects=1, ip_no_pmtu_disc=0) are the right values for honoring PTB.

3. Live trace: while we have an open TCP flow with a small MSS (we run our test from 2607:fae0:a000::42 on odin, 2a00:8642:42::75 on go6lab, 2a12:d8c0:105a:9001::a154 on karsolink, 2a09:ab81::91 on belgrade, 2a01:261:313:b814:2a0:98ff:fe5b:13e4 on t2, 2a06:d1c1:10a::bbbb on amsterdam, 2a06:d1c1:10d::aaaa on duseldorf and 2a06:d1c1:10b::cccc on berlin), watch for our forged Type 2 arriving on your interface:

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 2a12:d8c0:105a:9001::a154 or src host 2a09:ab81::91 or src host 2a01:261:313:b814:2a0:98ff:fe5b:13e4 or src host 2a06:d1c1:10a::bbbb or src host 2a06:d1c1:10d::aaaa or src host 2a06:d1c1:10b::cccc)'

If you see our PTBs arriving but TCP segments still stay big, the drop is in your kernel or NIC offload (cause 3). If you don't see them at all, the drop is upstream of you (cause 2) - ask your upstream(s) to permit ICMPv6 Type 2.

4. If your test target above (2026-09-23T12:01:22Z) is a host that you don't own (e.g. a third-party DNS / TLS server you happen to operate prefixes for), the verdict reflects that specific host's behaviour - try the test against a server you do own and we'll happily re-run.

RFC 4890 references: §4.3.1 (Packet Too Big - MUST NOT be dropped), and RFC 8201 for the broader PMTUD requirement.

Where the path divergence is

Per-vantage probe + verdict (headline):

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

vantageicmp6-echodns-tcptlshttp
belgradehonoredinconclusiveno_tcpno_tcp
berlinhonoredinconclusiveno_tcpno_tcp
duseldorfnot_honoredinconclusiveno_tcpno_tcp
go6labnot_honoredinconclusiveno_tcpno_tcp
karsolinkhonoredinconclusiveno_tcpno_tcp
odinhonoredinconclusiveno_tcpno_tcp
t2not_honoredinconclusiveno_tcpno_tcp

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): AS2597, AS137, AS6762.

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.

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:d40:1:1::5

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:8::3a
32001:7f8:1e:8::3d
42001:67c:128c::699
52a00:d40:1:1::5
berlin - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:401
32001:4ba0:92f4:3::1
4<span class='muted'>no reply</span>
52001:4ba0:ffe9:109::2
62001:4ba0:ffe9:8a::2
72001:4ba0:ffe9:103e::1
82001:4ba0:ffe9:103b::1
92001:4ba0:ffe9:b8::
102001:4ba0:ffe9:a7::1
112001:4ba0:ffe9:da::2
122001:4ba0:ffe9:db::2
132001:7f8:b:100:1d1:a5d0:137:39
142001:760:ffff:ffaa::180:159
152001:760:ffff:ffaa::180:160
162001:760:ffff:104::7
172001:760:ffff:120::11
182a00:d40:1:2::82
192a00:d40:1:2::82
duseldorf - verdict not_honored

verdict = not_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:ffe9:8a::2
62001:4ba0:ffe9:103e::1
72001:4ba0:ffe9:103b::1
82001:4ba0:ffe9:b8::
92001:4ba0:ffe9:a7::1
102001:4ba0:ffe9:da::2
112001:4ba0:ffe9:db::2
122001:7f8:b:100:1d1:a5d0:137:39
132001:760:ffff:ffaa::180:156
142001:760:ffff:ffaa::180:167
152001:760:ffff:104::7
162a00:d40:2:2::
172a00:d40:1:2::82
182a00:d40:1:2::82
192a00:d40:1:1::5
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
32a00:1ca8:1::194
42a03:3f40::10:41
52a01:3e0:30:1::1
62a01:3e0:701::7
72a01:3e0:701::11
8<span class='muted'>no reply</span>
92001:41a8:100:2::139
102001:41a8:20::47
112001:41a8:20:2::43a
122a00:d40:1:2::9
132a00:d40:1:2::82
142a00:d40:6::1
152a00:d40:1:1::5
karsolink - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:109f:106::a2
42001:7f8:5f:ffff::12
52001:760:ffff:ffbb::181:21
62001:760:ffff:ffbb::181:11
72001:760:ffff:ffaa::180:160
82001:760:ffff:104::7
92a00:d40:2:2::
102a00:d40:1:2::9
112a00:d40:1:2::82
122a00:d40:6::1
132a00:d40:1:1::5
odin - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a00:ee1:800:9::1
42a00:ee0:1:10::2
52a00:ee0:1:10::2
62001:41a8:20::33
72001:41a8:20:2::43a
82a00:d40:1:2::9
92a00:d40:1:2::9
102a00:d40:1:2::82
112a00:d40:1:1::5
t2 - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9a
42a01:260:1:1::39
52001:7f8:13::a500:6939:1
62001:470:0:349::1
72001:470:0:349::1
82001:470:0:2f6::2
92001:41a8:20::47
102001:41a8:20:2::43a
112a00:d40:1:2::82
122a00:d40:1:2::82
132a00:d40:1:1::5

Target 2a00:d40:1:1:192:12:192:20

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:8::3a
32001:7f8:1e:8::3d
42001:67c:128c::699
52a00:d40:1:1:192:12:192:20
berlin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:401
32001:4ba0:92f4:3::1
4<span class='muted'>no reply</span>
52001:4ba0:ffe9:109::2
62001:4ba0:ffe9:8a::2
72001:4ba0:ffe9:103e::1
82001:4ba0:ffe9:103b::1
92001:4ba0:ffe9:b8::
102001:4ba0:ffe9:a7::1
112001:4ba0:ffe9:da::2
122001:4ba0:ffe9:db::2
132001:7f8:b:100:1d1:a5d0:137:39
142001:760:ffff:ffbb::181:68
152001:760:ffff:ffaa::180:160
162001:760:ffff:ffee::221:1
172a00:d40:2:2::
182a00:d40:1:2::9
192a00:d40:1:2::82
202a00:d40:6::1
212a00:d40:1:1:192:12:192:20
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:ffe9:8a::2
62001:4ba0:ffe9:103e::1
72001:4ba0:ffe9:103b::1
82001:4ba0:ffe9:b8::
92001:4ba0:ffe9:a7::1
102001:4ba0:ffe9:da::2
112001:4ba0:ffe9:db::2
122001:7f8:b:100:1d1:a5d0:137:39
132001:760:ffff:ffaa::180:156
142001:760:ffff:ffbb::181:118
152001:760:ffff:104::7
162a00:d40:2:2::
172a00:d40:1:2::9
182a00:d40:1:2::82
192a00:d40:1:1:192:12:192:20
go6lab - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a00:8642:1000:f000::1
32a00:1ca8:1::194
42a03:3f40::10:41
52a01:3e0:30:1::1
62a01:3e0:701::7
7<span class='muted'>no reply</span>
8<span class='muted'>no reply</span>
92001:41a8:100:2::139
102001:41a8:20::47
112001:41a8:20:2::43a
122a00:d40:1:2::9
132a00:d40:1:2::82
142a00:d40:6::1
152a00:d40:1:1:192:12:192:20
karsolink - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:109f:106::a2
42001:7f8:5f:ffff::12
52001:760:ffff:ffbb::181:21
62001:760:ffff:ffbb::181:11
72001:760:ffff:ffaa::180:160
82001:760:ffff:104::7
92a00:d40:2:2::
102a00:d40:1:2::9
112a00:d40:1:2::82
122a00:d40:6::1
132a00:d40:1:1:192:12:192:20
odin - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a00:ee1:800:9::1
42a00:ee0:1:10::2
52a00:ee0:1:15::2
62001:41a8:20::33
72001:41a8:20:2::416
82a00:d40:1:2::9
92a00:d40:1:2::9
102a00:d40:1:2::82
112a00:d40:6::1
122a00:d40:1:1:192:12:192:20
t2 - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9a
42a01:260:1:1::39
5<span class='muted'>no reply</span>
62001:470:0:349::1
72001:470:0:2f6::2
82001:41a8:20::47
92001:41a8:20:2::43a
102001:41a8:20:2::43a
112a00:d40:1:2::9
122a00:d40:1:2::82
132a00:d40:6::1
142a00:d40:1:1:192:12:192:20

Target 2a00:d40:1:1:192:12:192:40

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:8::3a
32001:7f8:1e:8::3d
42001:67c:128c::699
52a00:d40:1:1:192:12:192:40
berlin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:401
32001:4ba0:92f4:3::1
4<span class='muted'>no reply</span>
52001:4ba0:ffe9:109::2
62001:4ba0:ffe9:8a::2
72001:4ba0:ffe9:103e::1
82001:4ba0:ffe9:103b::1
92001:4ba0:ffe9:b8::
102001:4ba0:ffe9:a7::1
112001:4ba0:ffe9:da::2
122001:4ba0:ffe9:db::2
132001:7f8:b:100:1d1:a5d0:137:39
142001:760:ffff:ffbb::181:68
152001:760:ffff:ffbb::181:118
162001:760:ffff:104::7
172001:760:ffff:120::11
182a00:d40:1:2::82
192a00:d40:6::1
202a00:d40:1:1:192:12:192:40
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:ffe9:8a::2
62001:4ba0:ffe9:103e::1
72001:4ba0:ffe9:103b::1
82001:4ba0:ffe9:b8::
92001:4ba0:ffe9:a7::1
102001:4ba0:ffe9:da::2
112001:4ba0:ffe9:db::2
122001:7f8:b:100:1d1:a5d0:137:39
132001:760:ffff:ffaa::180:156
142001:760:ffff:ffbb::181:34
152001:760:ffff:ffee::221:3
162a00:d40:2:2::
172a00:d40:1:2::9
182a00:d40:1:2::82
192a00:d40:1:1:192:12:192:40
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
32a00:1ca8:1::194
42a03:3f40::10:41
52a01:3e0:30:1::1
62a01:3e0:701::7
7<span class='muted'>no reply</span>
8<span class='muted'>no reply</span>
92001:41a8:100:2::139
102001:41a8:20::47
112001:41a8:20:2::43a
122a00:d40:1:2::9
132a00:d40:1:2::82
142a00:d40:6::1
152a00:d40:1:1:192:12:192:40
karsolink - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:109f:106::a2
42001:7f8:5f:ffff::12
52001:760:ffff:ffbb::181:21
62001:760:ffff:ffbb::181:11
72001:760:ffff:ffaa::180:160
82001:760:ffff:104::7
92a00:d40:2:2::
102a00:d40:1:2::9
112a00:d40:1:2::82
122a00:d40:6::1
132a00:d40:1:1:192:12:192:40
odin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a00:ee1:800:9::1
42a00:ee0:1:10::2
52a00:ee0:1:10::2
62001:41a8:20::47
72001:41a8:20:2::43a
82a00:d40:1:2::9
92a00:d40:1:2::82
102a00:d40:6::1
112a00:d40:1:1:192:12:192:40
t2 - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9c
42001:7f8:13::a500:6939:1
52001:7f8:13::a500:6939:1
6<span class='muted'>no reply</span>
72001:470:0:2f6::2
82001:470:0:2f6::2
92001:41a8:20:2::43a
102a00:d40:1:2::9
112a00:d40:1:2::82
122a00:d40:1:2::82
132a00:d40:1:1:192:12:192:40

Target 2a00:d40:1:1::2

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:8::3a
32001:7f8:1e:8::3d
42001:67c:128c::699
52a00:d40:1:1::2
berlin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:401
32001:4ba0:92f4:3::1
4<span class='muted'>no reply</span>
52001:4ba0:ffe9:109::2
62001:4ba0:ffe9:8a::2
72001:4ba0:ffe9:103e::1
82001:4ba0:ffe9:103b::1
92001:4ba0:ffe9:b8::
102001:4ba0:ffe9:a7::1
112001:4ba0:ffe9:da::2
122001:4ba0:ffe9:db::2
132001:7f8:b:100:1d1:a5d0:137:39
142001:760:ffff:ffbb::181:68
152001:760:ffff:ffbb::181:34
162001:760:ffff:104::7
172001:760:ffff:120::11
182a00:d40:1:2::82
192a00:d40:6::1
202a00:d40:1:1::2
duseldorf - verdict not_honored

verdict = not_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:ffe9:8a::2
62001:4ba0:ffe9:103e::1
72001:4ba0:ffe9:103b::1
82001:4ba0:ffe9:b8::
92001:4ba0:ffe9:a7::1
102001:4ba0:ffe9:da::2
112001:4ba0:ffe9:db::2
122001:7f8:b:100:1d1:a5d0:137:39
132001:760:ffff:ffbb::181:68
142001:760:ffff:ffaa::180:160
152001:760:ffff:ffee::221:1
162a00:d40:2:2::
172a00:d40:1:2::9
182a00:d40:6::1
192a00:d40:6::1
202a00:d40:1:1::2
go6lab - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a00:8642:1000:f000::1
32a00:1ca8:1::194
42a03:3f40::10:41
52a01:3e0:30:1::1
62a01:3e0:701::7
72a01:3e0:701::f
8<span class='muted'>no reply</span>
92001:41a8:100:2::139
102001:41a8:20::47
112001:41a8:20:2::43a
122a00:d40:1:2::9
132a00:d40:1:2::82
142a00:d40:6::1
152a00:d40:1:1::2
karsolink - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:109f:106::a2
42001:7f8:5f:ffff::12
52001:760:ffff:ffbb::181:21
62001:760:ffff:ffbb::181:11
72001:760:ffff:ffaa::180:160
82001:760:ffff:104::7
92a00:d40:2:2::
102a00:d40:1:2::9
112a00:d40:1:2::82
122a00:d40:6::1
132a00:d40:1:1::2
odin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a00:ee1:800:9::1
42a00:ee0:1:15::2
52a00:ee0:1:10::2
62001:41a8:20::33
72001:41a8:20:2::43a
82a00:d40:1:2::9
92a00:d40:1:2::9
102a00:d40:1:2::82
112a00:d40:6::1
122a00:d40:1:1::2
t2 - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9c
42a01:260:1:1::39
52001:7f8:13::a500:6939:1
6<span class='muted'>no reply</span>
72001:470:0:349::1
82001:470:0:2f6::2
92001:41a8:20::47
102001:41a8:20:2::43a
112a00:d40:1:2::82
122a00:d40:1:2::82
132a00:d40:1:1::2

Target 2a00:d40:1:1::3

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:8::3a
32001:7f8:1e:8::3d
42001:67c:128c::699
52a00:d40:1:1::3
berlin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a06:d1c0::dead:beef:401
32001:4ba0:92f4:3::1
4<span class='muted'>no reply</span>
52001:4ba0:ffe9:109::2
62001:4ba0:ffe9:8a::2
72001:4ba0:ffe9:103e::1
82001:4ba0:ffe9:103b::1
92001:4ba0:ffe9:b8::
102001:4ba0:ffe9:a7::1
112001:4ba0:ffe9:da::2
122001:4ba0:ffe9:db::2
132001:7f8:b:100:1d1:a5d0:137:39
142001:760:ffff:ffbb::181:68
152001:760:ffff:ffbb::181:34
162001:760:ffff:104::7
172001:760:ffff:120::11
182a00:d40:1:2::9
192a00:d40:1:2::82
202a00:d40:1:1::3
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:ffe9:8a::2
62001:4ba0:ffe9:103e::1
72001:4ba0:ffe9:103b::1
82001:4ba0:ffe9:b8::
92001:4ba0:ffe9:a7::1
102001:4ba0:ffe9:da::2
112001:4ba0:ffe9:db::2
122001:7f8:b:100:1d1:a5d0:137:39
132001:760:ffff:ffaa::180:159
142001:760:ffff:ffaa::180:160
152001:760:ffff:ffee::221:1
162a00:d40:2:2::
172a00:d40:1:2::82
182a00:d40:1:2::82
192a00:d40:1:1::3
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
32a00:1ca8:1::194
42a03:3f40::10:41
52a01:3e0:30:1::1
62a01:3e0:701::7
72a01:3e0:701::11
8<span class='muted'>no reply</span>
92001:41a8:100:2::139
102001:41a8:20::47
112001:41a8:20:2::43a
122a00:d40:1:2::9
132a00:d40:1:2::82
14<span class='muted'>no reply</span>
152a00:d40:1:1::3
karsolink - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a12:d8c0:109f:121::a1
32a12:d8c0:109f:106::a2
42001:7f8:5f:ffff::12
52001:760:ffff:ffbb::181:21
62001:760:ffff:ffbb::181:11
72001:760:ffff:ffaa::180:160
82001:760:ffff:104::7
92a00:d40:2:2::
102a00:d40:1:2::9
112a00:d40:1:2::82
122a00:d40:6::1
132a00:d40:1:1::3
odin - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a00:ee1:800:9::1
42a00:ee0:1:15::2
52a00:ee0:1:10::2
62001:41a8:20::33
72001:41a8:20:2::43a
82a00:d40:1:2::9
92a00:d40:1:2::82
102a00:d40:6::1
112a00:d40:1:1::3
t2 - verdict not_honored

verdict = not_honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22a01:260:1::225
32a01:260:1:1::9c
42a01:260:1:1::39
5<span class='muted'>no reply</span>
62001:470:0:349::1
72001:470:0:2f6::2
82001:470:0:2f6::2
92001:41a8:20:2::43a
102a00:d40:1:2::9
112a00:d40:1:2::9
122a00:d40:1:2::82
132a00:d40:1:1::3

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 AS2597

From SRB host (SOX, Belgrade)   openRFC 4890 ✓

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

4/4
Echo small (56B) 58.2ms
4/4
Echo 1500B (DF) 58.2ms
yes
Type 1 dest-unreach
443,80
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
0.2ms0%AS13004SOX - Serbian Open Exchange DOO, RS
32001:7f8:1e:8::3d0.3ms0%AS13004SOX - Serbian Open Exchange DOO, RS
4*-0%-
5dns.nic.it
2a00:d40:1:1::5
49.9ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

tracepath -6

 1?: [LOCALHOST]                        0.012ms pmtu 1500
 1:  _gateway                                              0.481ms 
 1:  _gateway                                              0.807ms 
 2:  sox-pn.sox.rs                                         1.159ms 
 3:  2001:7f8:1e:8::3d                                     0.865ms asymm  2 
 4:  2001:67c:128c::699                                   17.061ms 
 5:  dns.nic.it                                           52.102ms reached
     Resume: pmtu 1500 hops 5 back 11 

From DE host (Berlin)   openRFC 4890 ✓

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

4/4
Echo small (56B) 43.6ms
4/4
Echo 1500B (DF) 43.6ms
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
0.2ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2xe-0-0-12-2412.gw01.dus01.as59645.net
2a06:d1c0::dead:beef:401
8.3ms0%AS59645WYBT-NET - Tobias Fiebig, DE
3eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
9.1ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag13.agr3-dus3.bb.wiit.network
2001:4ba0:ffe9:7d::1
12.1ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
8.2ms0%AS24961MYLOC-AS - WIIT AG, DE
6lag0-vl1011.core1-fra-ix.bb.wiit.network
2001:4ba0:ffe9:8a::2
12.6ms0%AS24961MYLOC-AS - WIIT AG, DE
7lag0-vl1001.core1-nbg-ncd.bb.wiit.network
2001:4ba0:ffe9:103e::1
24.2ms0%AS24961MYLOC-AS - WIIT AG, DE
8lag0-vl6.core2-nbg-ncd.bb.wiit.network
2001:4ba0:ffe9:103b::1
15.1ms0%AS24961MYLOC-AS - WIIT AG, DE
92001:4ba0:ffe9:b819.1ms0%-
10lag0-vl1009.core1-muc-eq3.bb.wiit.network
2001:4ba0:ffe9:a7::1
17.9ms0%AS24961MYLOC-AS - WIIT AG, DE
11lag0-vl1001.core1-pda-vsix.bb.wiit.network
2001:4ba0:ffe9:da::2
28.4ms0%AS24961MYLOC-AS - WIIT AG, DE
12lag0-vl1001.core1-mil-mix.bb.wiit.network
2001:4ba0:ffe9:db::2
28.0ms0%AS24961MYLOC-AS - WIIT AG, DE
13garr-v6.mix-it.net @MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO
2001:7f8:b:100:1d1:a5d0:137:39
28.2ms0%-NA
14re1-mi02-rs1-mi02.mi02.garr.net
2001:760:ffff:ffaa::180:156
28.3ms0%AS137ASGARR - Consortium GARR, IT
15rs1-mi02-rs1-to01.to01.garr.net
2001:760:ffff:ffbb::181:118
30.5ms0%AS137ASGARR - Consortium GARR, IT
162001:760:ffff:ffee::221:336.9ms0%AS137ASGARR - Consortium GARR, IT
172001:760:ffff:120::1141.4ms0%AS137ASGARR - Consortium GARR, IT
18p1-pi-ospf-p1-mi.nic.it
2a00:d40:1:2::9
34.6ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
19p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
39.5ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
20dns.nic.it
2a00:d40:1:1::5
46.4ms60%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

Rate-limited ICMPv6: hop 20 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.032ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.600ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.525ms 
 2:  xe-0-0-12-2412.gw01.dus01.as59645.net                 8.574ms 
 3:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            9.961ms 
 4:  no reply
 5:  lag11.core3-dus1.bb.wiit.network                      8.475ms 
 6:  lag0-vl1011.core1-fra-ix.bb.wiit.network             12.564ms 
 7:  lag0-vl1001.core1-nbg-ncd.bb.wiit.network            15.326ms 
 8:  lag0-vl6.core2-nbg-ncd.bb.wiit.network               15.417ms 
 9:  lag0-vl1006.core2-muc2.bb.wiit.network               17.677ms 
10:  lag0-vl1009.core1-muc-eq3.bb.wiit.network            18.163ms 
11:  lag0-vl1001.core1-pda-vsix.bb.wiit.network           28.528ms 
12:  lag0-vl1001.core1-mil-mix.bb.wiit.network            28.732ms asymm 10 
13:  garr-v6.mix-it.net                                   28.447ms asymm 11 
14:  re1-mi02-rs1-rm02.rm02.garr.net                      36.097ms asymm 12 
15:  rs1-mi01-rl1-mi02.mi02.garr.net                      35.561ms asymm 13 
16:  rl1-mi02-ru-registroit-l2.mi02.garr.net              30.003ms asymm  7 
17:  2001:760:ffff:120::11                                44.743ms asymm  7 
18:  p1-pi-ospf-p1-mi.nic.it                              34.515ms asymm  7 
19:  p2-pi-ospf-p1-pi.nic.it                              40.228ms asymm  8 
20:  dns.nic.it                                           43.799ms reached
     Resume: pmtu 1500 hops 20 back 10 

From DE host (Düsseldorf)   openRFC 4890 ✗

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

4/4
Echo small (56B) 34.7ms
4/4
Echo 1500B (DF) 34.8ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
21.0ms0%AS24961MYLOC-AS - WIIT AG, DE
3lag10-h5f01.agr4-dus1.bb.wiit.network
2001:4ba0:ffe9:7c::1
156.7ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
0.1ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag0-vl1011.core1-fra-ix.bb.wiit.network
2001:4ba0:ffe9:8a::2
4.1ms0%AS24961MYLOC-AS - WIIT AG, DE
6lag0-vl1001.core1-nbg-ncd.bb.wiit.network
2001:4ba0:ffe9:103e::1
6.7ms0%AS24961MYLOC-AS - WIIT AG, DE
7lag0-vl6.core2-nbg-ncd.bb.wiit.network
2001:4ba0:ffe9:103b::1
7.1ms0%AS24961MYLOC-AS - WIIT AG, DE
82001:4ba0:ffe9:b89.6ms0%-
9lag0-vl1009.core1-muc-eq3.bb.wiit.network
2001:4ba0:ffe9:a7::1
9.7ms0%AS24961MYLOC-AS - WIIT AG, DE
10lag0-vl1001.core1-pda-vsix.bb.wiit.network
2001:4ba0:ffe9:da::2
20.2ms0%AS24961MYLOC-AS - WIIT AG, DE
11lag0-vl1001.core1-mil-mix.bb.wiit.network
2001:4ba0:ffe9:db::2
19.9ms0%AS24961MYLOC-AS - WIIT AG, DE
12garr-v6.mix-it.net @MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO
2001:7f8:b:100:1d1:a5d0:137:39
20.4ms0%-NA
13re1-mi02-rs1-mi02.mi02.garr.net
2001:760:ffff:ffaa::180:156
20.6ms0%AS137ASGARR - Consortium GARR, IT
14rs1-mi02-rl1-mi02.mi02.garr.net
2001:760:ffff:ffaa::180:167
74.5ms0%AS137ASGARR - Consortium GARR, IT
15rl1-mi02-ru-registroit-l2.mi02.garr.net
2001:760:ffff:104::7
21.0ms0%AS137ASGARR - Consortium GARR, IT
162a00:d40:2:227.9ms0%-
17p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
29.6ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
18p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
27.0ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
19dns.nic.it
2a00:d40:1:1::5
34.4ms60%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

Rate-limited ICMPv6: hop 19 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.037ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.478ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.293ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            5.919ms 
 3:  no reply
 4:  lag30.core3-dus1.bb.wiit.network                      0.321ms 
 5:  lag0-vl1011.core1-fra-ix.bb.wiit.network              4.268ms 
 6:  lag0-vl1001.core1-nbg-ncd.bb.wiit.network             6.948ms 
 7:  lag0-vl6.core2-nbg-ncd.bb.wiit.network                6.732ms 
 8:  lag0-vl1006.core2-muc2.bb.wiit.network                9.521ms 
 9:  lag0-vl1009.core1-muc-eq3.bb.wiit.network             9.656ms 
10:  lag0-vl1001.core1-pda-vsix.bb.wiit.network           20.148ms 
11:  lag0-vl1001.core1-mil-mix.bb.wiit.network            20.183ms asymm  9 
12:  garr-v6.mix-it.net                                   20.150ms asymm 10 
13:  re1-mi02-rs1-mi02.mi02.garr.net                      20.510ms asymm 11 
14:  rs1-mi02-rl1-mi02.mi02.garr.net                      20.621ms asymm 12 
15:  rl1-mi02-ru-registroit-l2.mi02.garr.net              21.414ms asymm  6 
16:  p1-mi-ospf-p2-mi.nic.it                              32.727ms asymm  5 
17:  p2-pi-ospf-p1-pi.nic.it                              26.803ms asymm  7 
18:  p2-pi-ospf-p1-pi.nic.it                              26.792ms asymm  7 
19:  fw-pi-ospf-p1-pi-p2-pi.nic.it                        34.879ms asymm  9 
20:  dns.nic.it                                           37.698ms reached
     Resume: pmtu 1500 hops 20 back 8 

From NL host (go6lab)   openRFC 4890 ✗

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

4/4
Echo small (56B) 42.1ms
4/4
Echo 1500B (DF) 42.0ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::23.8ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2gw.friends.steffann.nl
2a00:8642:1000:f000::1
1.5ms0%*AS203993GNA-DC1-AS - S.J.M. Steffann, NL
32a00:1ca8:1::1944.2ms10%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:411.1ms0%AS50673Serverius-as - Serverius Holding B.V., NL
5ix-et-9-1-2.tcore1.ad1-amsterdam.ipv6.as6453.net
2a01:3e0:30:1::1
4.9ms0%AS6453AS6453 - TATA COMMUNICATIONS (AMERICA) INC, US
6if-bundle-2-2.qcore1.ad1-amsterdam.ipv6.as6453.net
2a01:3e0:701::7
3.6ms0%AS6453AS6453 - TATA COMMUNICATIONS (AMERICA) INC, US
7if-bundle-51-2.qcore1.av2-amsterdam.ipv6.as6453.net
2a01:3e0:701::f
4.6ms30%AS6453AS6453 - TATA COMMUNICATIONS (AMERICA) INC, US
8*-70%-
92001:41a8:100:2::13910.6ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
102001:41a8:20::4724.3ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
112001:41a8:20:2::43a35.3ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
12p1-pi-ospf-p1-mi.nic.it
2a00:d40:1:2::9
28.7ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
13p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
36.5ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
14fw-pi-ospf-p1-pi-p2-pi.nic.it
2a00:d40:6::1
27.8ms60%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
15dns.nic.it
2a00:d40:1:1::5
32.9ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

Rate-limited ICMPv6: hop 3, hop 7, hop 8, hop 14 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.047ms pmtu 1500
 1:  2a00:8642:42::2                                       1.529ms 
 1:  2a00:8642:42::2                                       2.006ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      3.232ms 
 4:  2a03:3f40::10:41                                      6.950ms 
 5:  ix-ge-100-0-0-66.qhar2.ad1-amsterdam.ipv6.as6453.net   7.850ms 
 6:  if-bundle-2-2.qcore1.ad1-amsterdam.ipv6.as6453.net   16.256ms 
 7:  no reply
 8:  no reply
 9:  2001:41a8:100:2::139                                 13.248ms asymm  8 
10:  2001:41a8:20::47                                     26.460ms 
11:  2001:41a8:20:2::43a                                  29.998ms asymm  9 
12:  p1-pi-ospf-p1-mi.nic.it                              30.309ms asymm 10 
13:  p2-pi-ospf-p1-pi.nic.it                              35.340ms asymm 11 
14:  fw-pi-ospf-p1-pi-p2-pi.nic.it                        32.026ms asymm 13 
15:  dns.nic.it                                           35.021ms reached
     Resume: pmtu 1500 hops 15 back 12 

From ITA host (Karsolink)   openRFC 4890 ✓

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

4/4
Echo small (56B) 14.9ms
3/4
Echo 1500B (DF) 15.0ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
2*-0%*-
32a12:d8c0:109f:106::a23.3ms90%AS204471KARSOLINK - 2S Computers SRL, IT
42001:7f8:5f:ffff::123.5ms0%-NA
5rl1-pd02-rs1-pd01.pd01.garr.net
2001:760:ffff:ffbb::181:21
8.3ms0%AS137ASGARR - Consortium GARR, IT
6rs1-pd01-rs1-mi01.mi01.garr.net
2001:760:ffff:ffbb::181:11
8.0ms0%AS137ASGARR - Consortium GARR, IT
7rs1-mi01-rl1-mi02.mi02.garr.net
2001:760:ffff:ffaa::180:160
7.9ms0%AS137ASGARR - Consortium GARR, IT
8rl1-mi02-ru-registroit-l2.mi02.garr.net
2001:760:ffff:104::7
9.6ms0%AS137ASGARR - Consortium GARR, IT
92a00:d40:2:29.6ms0%-
10p1-pi-ospf-p1-mi.nic.it
2a00:d40:1:2::9
14.8ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
11p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
31.4ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
12fw-pi-ospf-p1-pi-p2-pi.nic.it
2a00:d40:6::1
14.9ms20%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
13dns.nic.it
2a00:d40:1:1::5
14.8ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

Rate-limited ICMPv6: hop 3, hop 12 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.045ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        1.692ms 
 2:  2a12:d8c0:109f:121::a1                                0.882ms 
 3:  2a12:d8c0:109f:106::a2                                3.551ms 
 4:  2001:7f8:5f:ffff::12                                  4.082ms 
 5:  rl1-pd02-rs1-pd01.pd01.garr.net                       8.496ms 
 6:  rs1-pd01-rs1-mi01.mi01.garr.net                       8.378ms asymm  5 
 7:  rs1-mi01-rl1-mi02.mi02.garr.net                       8.663ms asymm  6 
 8:  rl1-mi02-ru-registroit-l2.mi02.garr.net              10.040ms asymm  9 
 9:  p1-mi-ospf-p2-mi.nic.it                              89.006ms asymm  8 
10:  p1-pi-ospf-p1-mi.nic.it                              15.542ms asymm  9 
11:  p2-pi-ospf-p1-pi.nic.it                              15.325ms asymm 10 
12:  fw-pi-ospf-p1-pi-p2-pi.nic.it                        15.430ms asymm 11 
13:  dns.nic.it                                           15.300ms reached
     Resume: pmtu 1500 hops 13 back 10 

From SLO host (6connect)   openRFC 4890 ✓

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

4/4
Echo small (56B) 15.3ms
4/4
Echo 1500B (DF) 15.3ms
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
32a00:ee1:800:9::11.8ms70%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
42a00:ee0:1:10::20.9ms0%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
52001:41a8:20:2::1698.5ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
6mil51-loop0-v6.mil.seabone.net
2001:41a8:20::33
14.5ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
72001:41a8:20:2::4169.8ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
8p1-pi-ospf-p1-mi.nic.it
2a00:d40:1:2::9
14.8ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
9p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
14.4ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
10p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
31.2ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
11dns.nic.it
2a00:d40:1:1::5
14.6ms70%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

Rate-limited ICMPv6: hop 3, hop 11 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.023ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.935ms 
 1:  fw1-lju.6connect.com                                  0.629ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     2.033ms 
 4:  2a00:ee0:1:15::2                                      1.629ms asymm  3 
 5:  2a00:ee0:1:15::2                                      1.797ms pmtu 1500
 5:  2001:41a8:20:2::169                                   9.050ms asymm  6 
 6:  mil51-loop0-v6.mil.seabone.net                        9.121ms 
 7:  2001:41a8:20:2::43a                                   8.973ms 
 8:  p1-mi-ospf-p2-mi.nic.it                               9.920ms asymm  7 
 9:  p2-pi-ospf-p1-pi.nic.it                              15.001ms asymm  8 
10:  fw-pi-ospf-p1-pi-p2-pi.nic.it                        14.821ms asymm 11 
11:  fw-pi-ospf-p1-pi-p2-pi.nic.it                        15.263ms asymm 10 
12:  dns.nic.it                                           14.750ms reached
     Resume: pmtu 1500 hops 12 back 11 

From SLO host (T-2)   openRFC 4890 ✗

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

4/4
Echo small (56B) 37.0ms
4/4
Echo 1500B (DF) 37.0ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
22a01:260:1::2252.1ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9c.core6.t-2.net
2a01:260:1:1::9c
2.3ms0%*AS34779T-2-AS - T-2, d.o.o., SI
4hurricane-electric.nikhef.nlsix.net
2001:7f8:13::a500:6939:1
37.2ms0%*-NA
5hurricane-electric.nikhef.nlsix.net
2001:7f8:13::a500:6939:1
34.9ms0%-NA
6be6.core3.par2.he.net
2001:470:0:349::1
40.3ms-AS6939HURRICANE - Hurricane Electric LLC, US
7seabone-net-as6762.port-channel7.core2.par2.he.net
2001:470:0:2f6::2
38.2ms50%AS6939HURRICANE - Hurricane Electric LLC, US
8seabone-net-as6762.port-channel7.core2.par2.he.net
2001:470:0:2f6::2
38.1ms0%AS6939HURRICANE - Hurricane Electric LLC, US
92001:41a8:20:2::43a34.0ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
102001:41a8:20:2::43a32.3ms0%AS6762SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT
11p1-pi-ospf-p1-mi.nic.it
2a00:d40:1:2::9
38.0ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
12p2-pi-ospf-p1-pi.nic.it
2a00:d40:1:2::82
42.2ms0%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT
13dns.nic.it
2a00:d40:1:1::5
40.6ms60%AS2597CCTLD-IT - Consiglio Nazionale delle Ricerche, IT

Rate-limited ICMPv6: hop 7, hop 13 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       6.847ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        3.547ms 
 4:  2a01-260-1-1--39.core6.t-2.net                        1.995ms asymm  3 
 5:  no reply
 6:  be6.core3.par2.he.net                                41.764ms 
 7:  be6.core3.par2.he.net                                42.225ms asymm  6 
 8:  seabone-net-as6762.port-channel7.core2.par2.he.net   40.480ms 
 9:  2001:41a8:20::47                                     33.917ms asymm  8 
10:  2001:41a8:20:2::43a                                  36.180ms asymm  8 
11:  p1-pi-ospf-p1-mi.nic.it                              40.183ms asymm  9 
12:  fw-pi-ospf-p1-pi-p2-pi.nic.it                        41.537ms asymm 11 
13:  dns.nic.it                                           41.152ms reached
     Resume: pmtu 1500 hops 13 back 12