AS12874 - FASTWEB Fastweb SpAPI/PARFC 4890 ✓RPKI ✓ 18/18ASPA -

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AS overview

Test target: 2001:b00:4:5:3:: · dns3.fastweb.it · address space: mixed · prefixes announced: 18

prefix(es): 2001:b07:e000::/36, 2001:b07::/32, 2001:b07:d000::/36, 2001:b07:a000::/36, 2001:b07:4000::/36, 2001:b07:3000::/36, 2001:b07:f000::/36, 2001:b07:7000::/36 (+10 more)

Targets & per-vantage-point probe results (2 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:b00:4:5:3::
dns3.fastweb.it
NSrefusedrefused-refusedrefused-refusedrefused-??-refusedrefused-refusedrefused-refusedrefused-
2001:b00:4:8:3::
dns4.fastweb.it
NSrefusedrefused-refusedrefused-refusedrefused-??-refusedrefused-refusedrefused-refusedrefused-

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 2014-07-02. IPv6 LAN: 2001:7f8:b:100:1d1:a5d1:2874:46. Locations: -.

RPKI & ASPA

18 of 18 prefix(es) covered by a valid ROA.

PrefixRPKI stateReasonCovering VRP(s)
2001:b07:e000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07::/32✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:d000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:a000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:4000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:3000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:f000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:7000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:6000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:2000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:5000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:9000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:c000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b00::/29✓ validmatched VRP (correct origin, length within maxLength)AS12874 /29 maxLen 29 (ripe)
2001:b07:b000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:8000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07:1000::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)
2001:b07::/36✓ validmatched VRP (correct origin, length within maxLength)AS12874 /32 maxLen 36 (ripe); AS12874 /29 maxLen 29 (ripe)

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

At least one router inside AS12874's announced prefix replied during the random-target probe. Hop(s): 2001:b00:1:1:1::12a, 2001:b00:1:1:1::12e, 2001:b00:1:1:1::15a, 2001:b00:1:1:1::15e, 2001:b00:1:1:1::1ab. 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 - 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::912001:b00:4:5:3::icmp6-echohonored2026-09-23T12:00:20Z
berlin2a06:d1c1:10b::cccc2001:b00:4:5:3::icmp6-echohonored2026-09-23T12:00:17Z
duseldorf2a06:d1c1:10d::aaaa2001:b00:4:5:3::icmp6-echohonored2026-09-23T12:00:17Z
go6lab2a00:8642:42::752001:b00:4:5:3::icmp6-echonot_honored2026-09-23T12:00:57Z
karsolink2a12:d8c0:105a:9001::a1542001:b00:4:5:3::icmp6-echohonored2026-09-23T12:00:19Z
odin2607:fae0:a000::422001:b00:4:5:3::icmp6-echohonored2026-09-23T12:00:17Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42001:b00:4:5:3::icmp6-echohonored2026-09-23T12:00:18Z

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 77 B before PTB): max DNS-over-TCP segment 77B; 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 105 B before PTB): max DNS-over-TCP segment 105B; 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-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpinconclusive (reply 105 B before PTB): max DNS-over-TCP segment 105B; 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-tcpno_tcp: no DNS response data
  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 105 B before PTB): max DNS-over-TCP segment 105B; 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 77 B before PTB): max DNS-over-TCP segment 77B; 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-echohonored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)
  2. dns-tcpinconclusive (reply 77 B before PTB): max DNS-over-TCP segment 77B; 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 1360 B; after, it was 1360 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 (2026-09-23T12:00:57Z) 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
duseldorfhonoredinconclusiveno_tcpno_tcp
go6labnot_honoredno_tcpno_tcpno_tcp
karsolinkhonoredinconclusiveno_tcpno_tcp
odinhonoredinconclusiveno_tcpno_tcp
t2honoredinconclusiveno_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): AS12874, AS3303, AS9002.

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 2001:b00:4:5:3::

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
42a02:2d8:0:a00e:232a::
52a02:2d8::57f5:e080
62001:7f8:b:100:1d1:a5d1:2874:46
72001:b00:1:1:3::137
82001:b00:1:1:1::1c3
92001:b00:3:1::
102001:b00:4:5:3::
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::220
42a00:c380:b200:230::5
52a00:c380:b200:230::92
62a00:c380:b200:230::139
72a00:c380:b200:230::187
82a00:c380:b200:230::222
92001:7f8:8::ce7:0:1
102001:918:100:3b::1
112001:918:100:2::1
122001:918:100:12::1
132001:918:100:5::1
142001:918:100:24::1
152001:918:100:11::1
162001:918:100:e::1
17<span class='muted'>no reply</span>
182001:b00:1:1:4::bb
192001:b00:1:1:1::180
202001:b00:1:1:1::1c5
212001:b00:3:1::
222001:b00:4:5:3::
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:ffe9:8::2
62001:7f8::324a:0:1
72001:b00:1:1:1::1ad
82001:b00:1:1:1::1c3
92001:b00:3:1::
102001:b00:4:5:3::
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::10:33
52001:7f8:1::a501:2874:1
62001:b00:1:1:3::13b
72001:b00:1:1:1::1c5
82001:b00:3:1::
92001:b00:4:5:3::
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::3
52001:b00:1:1:3::137
62001:b00:1:1:1::1c5
72001:b00:3:1::
82001:b00:4:5:3::
odin - verdict honored

verdict = honored; final pmtu = 1500

#hop IPpmtu change
1<span class='muted'>no reply</span>
22607:fae0:a000:2::2
32a03:a100:0:201:1::1
42a03:a100:0:201:1::1
52001:918:100:74::1
62001:918:100:e::1
72001:4d98:a000::f9
82001:b00:1:1:2::5
92001:b00:1:1:1::17c
102001:b00:1:1:1::1c5
112001:b00:3:1::
122001:b00:4:5:3::
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
42001:7f8:46:0:1::3303
52001:918:100:74::1
62001:918:100:e::1
72001:4d98:a000::f9
82001:b00:1:1:4::bb
92001:b00:1:1:1::180
102001:b00:1:1:1::1c3
112001:b00:3:1::
122001:b00:4:5:3::

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 AS12874

From SRB host (SOX, Belgrade)   openRFC 4890 ✓

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

4/4
Echo small (56B) 29.0ms
4/4
Echo 1500B (DF) 29.0ms
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::3d0.3ms0%AS13004SOX - Serbian Open Exchange DOO, RS
42a02:2d8:0:a00e:232a12.6ms0%-
5RT.MIX.MIL.IT.retn.net
2a02:2d8::57f5:e080
23.9ms0%AS9002RETN-AS - RETN Limited, GB
6fastweb-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:a5d1:2874:46
92.0ms70%-NA
72001:b00:1:1:3::13728.9ms0%AS12874FASTWEB - Fastweb SpA, IT
82001:b00:1:1:1::1c329.4ms50%AS12874FASTWEB - Fastweb SpA, IT
92001:b00:3:129.0ms0%-
102001:b00:4:5:328.9ms0%-

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

tracepath -6

 1?: [LOCALHOST]                        0.015ms pmtu 1500
 1:  _gateway                                              0.771ms 
 1:  _gateway                                              0.366ms 
 2:  sox-pn.sox.rs                                         0.814ms 
 3:  2001:7f8:1e:8::3d                                     0.837ms asymm  2 
 4:  ae8-930.RT.IRX.VIE.AT.retn.net                       13.018ms asymm  3 
 5:  RT.MIX.MIL.IT.retn.net                               24.321ms asymm  4 
 6:  fastweb-v6.mix-it.net                                29.951ms asymm  5 
 7:  2001:b00:1:1:3::135                                  29.351ms asymm  6 
 8:  2001:b00:1:1:1::1c5                                  29.571ms asymm  7 
 9:  2001:b00:3:1::                                       29.160ms asymm  8 
10:  2001:b00:4:5:3::                                     29.051ms reached
     Resume: pmtu 1500 hops 10 back 9 

From DE host (Berlin)   openRFC 4890 ✓

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

4/4
Echo small (56B) 34.6ms
4/4
Echo 1500B (DF) 34.6ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*-0%*-
2ae0-2453.cr10.ber01.lwlcom.net
2a06:d1c0::dead:beef:1c02
1.9ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3ae0-10.cr10.ber03.lwlcom.net
2a00:c380:b200:230::220
2.1ms0%AS50629LWLCOM - LWLcom GmbH, DE
4ae0-15.cr11.dtm01.lwlcom.net
2a00:c380:b200:230::5
9.5ms0%AS50629LWLCOM - LWLcom GmbH, DE
5ae0-20.cr10.dtm01.lwlcom.net
2a00:c380:b200:230::92
9.1ms0%AS50629LWLCOM - LWLcom GmbH, DE
6ae0-50.cr10.dus02.lwlcom.net
2a00:c380:b200:230::24
9.0ms0%AS50629LWLCOM - LWLcom GmbH, DE
7ae0-20.cr10.dus01.lwlcom.net
2a00:c380:b200:230::108
9.0ms0%AS50629LWLCOM - LWLcom GmbH, DE
8ae0-90.cr11.dus01.lwlcom.net
2a00:c380:b200:230::222
15.2ms0%AS50629LWLCOM - LWLcom GmbH, DE
9as3303.dusseldorf.megaport.com
2001:7f8:8::ce7:0:1
17.1ms0%-NA
10i00ffm-005-loo179.bb.ip-plus.net
2001:918:100:3b::1
17.4ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
11i62bsw-015-loo179.ip6.ip-plus.net
2001:918:100:2::1
17.3ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
12i62bsg-015-loo179.bb.ip-plus.net
2001:918:100:12::1
17.3ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
13i73aar-015-loo179.bb.ip-plus.net
2001:918:100:5::1
17.2ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
14i71lzw-015-loo179.bb.ip-plus.net
2001:918:100:24::1
17.7ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
15i63lgv-015-loo179.bb.ip-plus.net
2001:918:100:11::1
19.9ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
16i00rom-005-loo179.bb.ip-plus.net
2001:918:100:e::1
29.4ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
17*---
182001:b00:1:1:4::bb31.1ms0%AS12874FASTWEB - Fastweb SpA, IT
192001:b00:1:1:1::18034.2ms0%AS12874FASTWEB - Fastweb SpA, IT
20*-70%-
212001:b00:3:131.3ms0%-
222001:b00:4:5:332.8ms0%-

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

tracepath -6

 1?: [LOCALHOST]                        0.027ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.472ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.545ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.870ms 
 3:  ae0-10.cr10.ber03.lwlcom.net                          0.987ms 
 4:  ae0-15.cr11.dtm01.lwlcom.net                          8.894ms asymm  5 
 5:  ae0-20.cr10.dtm01.lwlcom.net                          8.619ms asymm  4 
 6:  ae0-50.cr10.dus02.lwlcom.net                          8.905ms asymm  3 
 7:  ae0-10.cr10.dus01.lwlcom.net                          8.757ms asymm  4 
 8:  ae0-90.cr11.dus01.lwlcom.net                          8.712ms asymm  5 
 9:  as3303.dusseldorf.megaport.com                       17.515ms asymm 13 
10:  i00ffm-005-loo179.bb.ip-plus.net                     19.105ms asymm 12 
11:  i62bsw-015-loo179.ip6.ip-plus.net                    17.509ms asymm 14 
12:  i62bsg-015-loo179.bb.ip-plus.net                     17.480ms asymm 13 
13:  i73aar-015-loo179.bb.ip-plus.net                     17.562ms asymm 12 
14:  i71lzw-015-loo179.bb.ip-plus.net                     18.051ms asymm 12 
15:  i63lgv-015-loo179.bb.ip-plus.net                     20.231ms asymm 13 
16:  i00rom-005-loo179.bb.ip-plus.net                     29.321ms asymm 14 
17:  no reply
18:  2001:b00:1:1:2::5                                    31.975ms asymm  9 
19:  2001:b00:1:1:1::180                                  34.594ms asymm  8 
20:  2001:b00:1:1:1::1c5                                  32.615ms asymm  9 
21:  2001:b00:3:1::                                       32.333ms asymm 10 
22:  2001:b00:4:5:3::                                     32.132ms reached
     Resume: pmtu 1500 hops 22 back 11 

From DE host (Düsseldorf)   openRFC 4890 ✓

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

4/4
Echo small (56B) 17.2ms
4/4
Echo 1500B (DF) 17.3ms
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
0.1ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
2.6ms0%AS24961MYLOC-AS - WIIT AG, DE
3lag13.agr3-dus3.bb.wiit.network
2001:4ba0:ffe9:7d::1
3.0ms0%AS24961MYLOC-AS - WIIT AG, DE
4lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
0.2ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag2.core1-dus-ix.bb.wiit.network
2001:4ba0:ffe9:4f::1
0.5ms0%AS24961MYLOC-AS - WIIT AG, DE
6*-80%-
72001:b00:1:1:1::1ab17.1ms0%AS12874FASTWEB - Fastweb SpA, IT
82001:b00:1:1:1::1c517.6ms30%AS12874FASTWEB - Fastweb SpA, IT
92001:b00:3:117.2ms0%-
102001:b00:4:5:317.2ms0%-

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

tracepath -6

 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.708ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.211ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network           17.759ms 
 3:  no reply
 4:  lag30.core3-dus1.bb.wiit.network                      0.396ms 
 5:  lag8.core1-dus-ix.bb.wiit.network                     0.494ms 
 6:  no reply
 7:  2001:b00:1:1:1::1ad                                  17.345ms 
 8:  2001:b00:1:1:1::1c3                                  17.869ms 
 9:  2001:b00:3:1::                                       17.482ms 
10:  2001:b00:4:5:3::                                     17.424ms reached
     Resume: pmtu 1500 hops 10 back 10 

From NL host (go6lab)   openRFC 4890 ✗

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

4/4
Echo small (56B) 26.3ms
4/4
Echo 1500B (DF) 25.9ms
yes
Type 1 dest-unreach
-
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
12a00:8642:42::21.4ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2*---
32a00:1ca8:1::1946.7ms0%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:336.5ms0%AS50673Serverius-as - Serverius Holding B.V., NL
52001:7f8:1::a501:2874:120.8ms0%-NA
62001:b00:1:1:3::13921.6ms0%AS12874FASTWEB - Fastweb SpA, IT
72001:b00:1:1:1::1c321.9ms80%AS12874FASTWEB - Fastweb SpA, IT
82001:b00:3:120.9ms0%-
92001:b00:4:5:322.5ms0%-

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

tracepath -6

 1?: [LOCALHOST]                        0.060ms pmtu 1500
 1:  2a00:8642:42::2                                       3.963ms 
 1:  2a00:8642:42::2                                       3.268ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      8.395ms 
 4:  2a03:3f40::10:33                                      9.370ms 
 5:  2001:7f8:1::a501:2874:1                              27.262ms 
 6:  2001:b00:1:1:3::139                                  24.709ms 
 7:  2001:b00:1:1:1::1c3                                  22.326ms 
 8:  2001:b00:3:1::                                       23.570ms 
 9:  2001:b00:4:5:3::                                     22.294ms reached
     Resume: pmtu 1500 hops 9 back 9 

From ITA host (Karsolink)   openRFC 4890 ✓

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

4/4
Echo small (56B) 9.2ms
3/4
Echo 1500B (DF) 9.5ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
2*---
32a12:d8c0:109f:106::a23.1ms-AS204471KARSOLINK - 2S Computers SRL, IT
42001:7f8:5f:ffff::38.9ms0%-NA
52001:b00:1:1:3::1358.8ms0%AS12874FASTWEB - Fastweb SpA, IT
62001:b00:1:1:1::1c39.7ms0%AS12874FASTWEB - Fastweb SpA, IT
72001:b00:3:18.3ms0%-
82001:b00:4:5:38.2ms0%-

tracepath -6

 1?: [LOCALHOST]                        0.045ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        2.088ms 
 1:  karsolink-01.net.karsolink.com                        0.673ms 
 2:  2a12:d8c0:109f:121::a1                                0.886ms 
 3:  2a12:d8c0:109f:106::a2                                3.485ms 
 4:  fastweb-v6.mix-it.net                                10.809ms 
 5:  2001:b00:1:1:3::137                                   9.445ms 
 6:  2001:b00:1:1:1::1c3                                   9.021ms 
 7:  2001:b00:3:1::                                        9.670ms 
 8:  2001:b00:4:5:3::                                      9.620ms reached
     Resume: pmtu 1500 hops 8 back 8 

From SLO host (6connect)   openRFC 4890 ✓

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

4/4
Echo small (56B) 19.6ms
3/4
Echo 1500B (DF) 19.7ms
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
0.4ms0%*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::10.7ms0%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
42001:7f8:46:0:1::33037.8ms0%AS51988ARNES-SIX - ARNES, SI
5i00mil-005-loo179.bb.ip-plus.net
2001:918:100:74::1
7.8ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
6i00rom-005-loo179.bb.ip-plus.net
2001:918:100:e::1
16.5ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
72001:4d98:a000::f917.2ms0%-NA
82001:b00:1:1:4::bb18.6ms0%AS12874FASTWEB - Fastweb SpA, IT
92001:b00:1:1:1::17c20.5ms0%AS12874FASTWEB - Fastweb SpA, IT
102001:b00:1:1:1::1c320.6ms0%AS12874FASTWEB - Fastweb SpA, IT
112001:b00:3:119.3ms0%-
122001:b00:4:5:319.1ms0%-

tracepath -6

 1?: [LOCALHOST]                        0.020ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.686ms 
 1:  fw1-lju.6connect.com                                  0.652ms 
 2:  no reply
 3:  2a03:a100:0:201:1::1                                  1.412ms 
 4:  2a03:a100:0:201:1::1                                  1.890ms pmtu 1500
 4:  2001:7f8:46:0:1::3303                                10.888ms asymm  5 
 5:  i00mil-005-loo179.bb.ip-plus.net                      8.434ms asymm  6 
 6:  i00rom-005-loo179.bb.ip-plus.net                     16.681ms asymm  7 
 7:  2001:4d98:a000::f9                                   17.834ms asymm  8 
 8:  2001:b00:1:1:4::bb                                   18.704ms asymm 10 
 9:  2001:b00:1:1:1::17c                                  19.517ms 
10:  2001:b00:1:1:1::1c3                                  19.827ms 
11:  2001:b00:3:1::                                       19.180ms 
12:  2001:b00:4:5:3::                                     22.182ms reached
     Resume: pmtu 1500 hops 12 back 12 

From SLO host (T-2)   openRFC 4890 ✓

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

4/4
Echo small (56B) 22.7ms
4/4
Echo 1500B (DF) 22.8ms
yes
Type 1 dest-unreach
443,80
TCP responds on

Path (traceroute + mtr + PTR)

#IP / PTRRTTmtr lossASAS holder
1*---
22a01:260:1::2252.3ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9c.core6.t-2.net
2a01:260:1:1::9c
2.7ms0%*AS34779T-2-AS - T-2, d.o.o., SI
42001:7f8:46:0:1::33039.1ms0%AS51988ARNES-SIX - ARNES, SI
5i00mil-005-loo179.bb.ip-plus.net
2001:918:100:74::1
9.2ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
6i00rom-005-loo179.bb.ip-plus.net
2001:918:100:e::1
44.6ms0%AS3303SWISSCOM - Swisscom (Schweiz) AG, CH
72001:4d98:a000::11519.1ms0%-NA
82001:b00:1:1:2::723.3ms0%AS12874FASTWEB - Fastweb SpA, IT
92001:b00:1:1:1::18025.2ms0%AS12874FASTWEB - Fastweb SpA, IT
102001:b00:1:1:1::1c324.6ms0%AS12874FASTWEB - Fastweb SpA, IT
112001:b00:3:124.0ms0%-
122001:b00:4:5:323.8ms0%-

tracepath -6

 1?: [LOCALHOST]                        0.027ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       3.003ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        2.784ms 
 4:  2001:7f8:46:0:1::3303                                 9.728ms 
 5:  i00mil-005-loo179.bb.ip-plus.net                     10.109ms 
 6:  i00rom-005-loo179.bb.ip-plus.net                     19.419ms 
 7:  2001:4d98:a000::f9                                   19.472ms 
 8:  2001:b00:1:1:2::7                                    24.220ms asymm  9 
 9:  2001:b00:1:1:1::17c                                  24.211ms asymm  8 
10:  2001:b00:1:1:1::1c5                                  25.330ms asymm  9 
11:  2001:b00:3:1::                                       23.518ms asymm 10 
12:  2001:b00:4:5:3::                                     23.764ms reached
     Resume: pmtu 1500 hops 12 back 11