AS overview
Test target: 2001:4b18:a000::a · static prefix probe · address space: mixed · prefixes announced: 6
prefix(es): 2001:4b18::/32, 2001:4b18:3000::/36, 2001:4b18:a000::/36, 2001:4b18:1000::/36, 2001:4b18:b000::/36, 2001:4b18:2000::/36
Targets & per-vantage-point probe results (1 target(s) across 7 vantage point(s))
Source codes (hover any badge for full description): CUR=curated · NS/SOA/MX=DNS records · SPF=SPF TXT · DRV=holder-derived (www, ns1, mail, gw, …) · ATL=RIPE Atlas · PDB=PeeringDB · WHOIS=RIPE whois · RDAP=RIPE RDAP · HIT=IPv6 Hitlist · RTR=in-prefix path hop (router) · PRB=static prefix probe · SYN=synthetic prefix::1 fallback
| Target IP / hostname | Source | SRB host (SOX, Belgrade) | DE host (Berlin) | DE host (Düsseldorf) | NL host (go6lab) | ITA host (Karsolink) | SLO host (6connect) | SLO host (T-2) | ||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ||
2001:4b18:a000::a | prb | ✗ | ✗ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✗ | ✗ | refused | refused | ✓ | ✗ | ✗ | ? | ? | ✓ | ✓ | ✗ | ? | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✗ | ✗ | refused | refused | ✓ |
RPKI & ASPA
0 of 6 prefix(es) covered by a valid ROA, 6 not-found.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2001:4b18::/32 | - not-found | no covering VRP | |
2001:4b18:3000::/36 | - not-found | no covering VRP | |
2001:4b18:a000::/36 | - not-found | no covering VRP | |
2001:4b18:1000::/36 | - not-found | no covering VRP | |
2001:4b18:b000::/36 | - not-found | no covering VRP | |
2001:4b18:2000::/36 | - not-found | no covering VRP |
Random-IP probe (yarrp) into the AS' prefixes
We probed 70 arbitrary IPv6 address(es) inside AS20746's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a01:20f2:c013::7 at hop 24 - that router answers ICMPv6 Echo. This is not in AS20746'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:
- SRB host (SOX, Belgrade): inconclusive: no Echo Reply to 1300-byte probe. (ICMPv6 Echo + forged PTB)
- DE host (Berlin): inconclusive: no Echo Reply to 1300-byte probe. (ICMPv6 Echo + forged PTB)
- DE host (Düsseldorf): inconclusive: no Echo Reply to 1300-byte probe. (ICMPv6 Echo + forged PTB)
- NL host (go6lab): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
- ITA host (Karsolink): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
- SLO host (6connect): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
- SLO host (T-2): Type 2 NOT honored. Forged PTB had no effect (filtered en route or stack ignored it). (ICMPv6 Echo + forged PTB)
Why they disagree - reachability mismatch: One vantage couldn't drive a flow at all to this destination (no Echo Reply or no responding TCP port), so the active test had no behavioural change to observe. The other vantage's verdict is the only meaningful one here.
Failure detail - what to grep in your logs
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| belgrade | 2a09:ab81::91 | 2001:4b18:a000::a | icmp6-echo | no_echo | 2026-09-23T11:59:43Z |
| berlin | 2a06:d1c1:10b::cccc | 2001:4b18:a000::a | icmp6-echo | no_echo | 2026-09-23T11:59:43Z |
| duseldorf | 2a06:d1c1:10d::aaaa | 2001:4b18:a000::a | icmp6-echo | no_echo | 2026-09-23T11:59:42Z |
| go6lab | 2a00:8642:42::75 | 2001:4b18:a000::a | icmp6-echo | not_honored | 2026-09-23T12:00:08Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2001:4b18:a000::a | icmp6-echo | not_honored | 2026-09-23T11:59:43Z |
| odin | 2607:fae0:a000::42 | 2001:4b18:a000::a | icmp6-echo | not_honored | 2026-09-23T11:59:41Z |
| t2 | 2a01:261:313:b814:2a0:98ff:fe5b:13e4 | 2001:4b18:a000::a | icmp6-echo | not_honored | 2026-09-23T11:59:41Z |
Attempt log (belgrade):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 111] Connection refusedtls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (berlin):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 111] Connection refusedtls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (duseldorf):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 111] Connection refusedtls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (go6lab):
icmp6-echo→ not_honored (reply shrank 1460→1460 B)dns-tcp→ no_tcp: connect failed: timed outtls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (karsolink):
icmp6-echo→ not_honored (reply shrank 1460→1460 B)dns-tcp→ no_tcp: connect failed: [Errno 111] Connection refusedtls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (odin):
icmp6-echo→ not_honored (reply shrank 1460→1460 B)dns-tcp→ no_tcp: connect failed: [Errno 111] Connection refusedtls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (t2):
icmp6-echo→ not_honored (reply shrank 1460→1460 B)dns-tcp→ no_tcp: connect failed: [Errno 111] Connection refusedtls→ no_tcp: TLS connect failedhttp→ no_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
- 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.
- 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.
- 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 (2026-09-23T12:00:08Z) 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):
- belgrade: probe
icmp6-echo→ verdictno_echo - berlin: probe
icmp6-echo→ verdictno_echo - duseldorf: probe
icmp6-echo→ verdictno_echo - go6lab: probe
icmp6-echo→ verdictnot_honored - karsolink: probe
icmp6-echo→ verdictnot_honored - odin: probe
icmp6-echo→ verdictnot_honored - t2: probe
icmp6-echo→ verdictnot_honored
Full per-method matrix (all four methods run at each vantage):
| vantage | icmp6-echo | dns-tcp | tls | http |
|---|---|---|---|---|
| belgrade | no_echo | no_tcp | no_tcp | no_tcp |
| berlin | no_echo | no_tcp | no_tcp | no_tcp |
| duseldorf | no_echo | no_tcp | no_tcp | no_tcp |
| go6lab | not_honored | no_tcp | no_tcp | no_tcp |
| karsolink | not_honored | no_tcp | no_tcp | no_tcp |
| odin | not_honored | no_tcp | no_tcp | no_tcp |
| t2 | not_honored | no_tcp | no_tcp | no_tcp |
✓ All vantages agree on method(s): icmp6-echo - the headline-method spread above is dispatcher noise, not a real Type 2 disagreement.
These vantage-level disagreements are rooted somewhere in the forward paths. Joining each per-vantage traceroute against the IP→AS lookup from our global yarrp mesh, the first hop where the paths land in different ASes is the most likely site of the offending filter / unreachable AS / Type 2 drop.
Suspect transit ASes (ranked by how often they appear at the divergence point on the path of the worse-classifying vantage): AS6762, AS20746, AS3257.
- From belgrade (icmp_blocked/Type-2=no_echo) the path enters AS20746 at hop 5; from berlin (open/Type-2=no_echo) the same hop is in AS3257. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (icmp_blocked/Type-2=no_echo) the path enters an opaque hop at hop 15; from duseldorf (icmp_blocked/Type-2=no_echo) the same hop is in AS20746. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (icmp_blocked/Type-2=no_echo) the path enters AS20746 at hop 5; from go6lab (open/Type-2=not_honored) the same hop is in AS174. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (icmp_blocked/Type-2=no_echo) the path enters an opaque hop at hop 15; from karsolink (echo_only/Type-2=not_honored) the same hop is in AS20746. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (icmp_blocked/Type-2=no_echo) the path enters AS20746 at hop 5; from odin (open/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (icmp_blocked/Type-2=no_echo) the path enters an opaque hop at hop 15; from t2 (open/Type-2=not_honored) the same hop is in AS20746. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=no_echo) the path enters an opaque hop at hop 8; from duseldorf (icmp_blocked/Type-2=no_echo) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=no_echo) the path enters AS3257 at hop 5; from go6lab (open/Type-2=not_honored) the same hop is in AS174. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=no_echo) the path enters an opaque hop at hop 8; from karsolink (echo_only/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=no_echo) the path enters AS3257 at hop 5; from odin (open/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=no_echo) the path enters an opaque hop at hop 9; from t2 (open/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (icmp_blocked/Type-2=no_echo) the path enters AS6762 at hop 8; from go6lab (open/Type-2=not_honored) the same hop is in AS174. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (icmp_blocked/Type-2=no_echo) the path enters AS6762 at hop 9; from karsolink (echo_only/Type-2=not_honored) the same hop is in an opaque hop. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (icmp_blocked/Type-2=no_echo) the path enters AS6762 at hop 8; from odin (open/Type-2=not_honored) the same hop is in an opaque hop. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (icmp_blocked/Type-2=no_echo) the path enters an opaque hop at hop 10; from t2 (open/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=not_honored) the path enters AS174 at hop 7; from karsolink (echo_only/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=not_honored) the path enters AS50673 at hop 3; from odin (open/Type-2=not_honored) the same hop is in AS5603. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=not_honored) the path enters AS174 at hop 6; from t2 (open/Type-2=not_honored) the same hop is in AS6939. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From karsolink (echo_only/Type-2=not_honored) the path enters AS6762 at hop 8; from odin (open/Type-2=not_honored) the same hop is in an opaque hop. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From karsolink (echo_only/Type-2=not_honored) the path enters an opaque hop at hop 9; from t2 (open/Type-2=not_honored) the same hop is in AS6762. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
- From odin (open/Type-2=not_honored) the path enters AS6762 at hop 6; from t2 (open/Type-2=not_honored) the same hop is in AS6939. Last common AS: AS20746. The disagreement is most likely rooted in one of those two transit ASes.
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
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 ↗
- ● SRB host (SOX, Belgrade)
- ● DE host (Berlin)
- ● DE host (Düsseldorf)
- ● NL host (go6lab)
- ● ITA host (Karsolink)
- ● SLO host (6connect)
- ● SLO host (T-2)
- ── solid line = echo reply, PTB honored (clean reach)
- — — dashed line = echo reply but PTB not honored (RFC 4890 violation)
- no line = no echo reply (never reached)
- ◉ target: green = clean, amber = reachable-but-violation / unreachable
- ⚠ suspected drop AS
- ⋯ silent (unanswered) hops
- ● IXP hop
From SRB host (SOX, Belgrade) icmp blocked
filter likely at: destination AS20746 (ASN-IDC) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a09:ab81::1 | 0.7ms | 0%* | AS60733 | PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS |
| 2 | sox-pn.sox.rs 2001:7f8:1e:8::3a | 0.5ms | 0% | AS13004 | SOX - Serbian Open Exchange DOO, RS |
| 3 | 2001:7f8:1e:8::3d | 0.4ms | 0% | AS13004 | SOX - Serbian Open Exchange DOO, RS |
| 4 | 2001:67c:128c::699 | 18.1ms | 0% | - | NA |
| 5 | 2001:4b18:a000::a | 42.4ms | - | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
tracepath -6
1?: [LOCALHOST] 0.021ms pmtu 1500
1: _gateway 0.283ms
1: _gateway 0.709ms
2: sox-pn.sox.rs 0.399ms
3: 2001:7f8:1e:8::3d 0.801ms asymm 2
4: 2001:67c:128c::699 17.698ms
5: 2001:4b18:a000::a 44.263ms reached
Resume: pmtu 1500 hops 5 back 13 From DE host (Berlin) open
filter likely at: (none) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | xe-0-0-13-178.gw01.ber01.as59645.net 2a06:d1c1:100:b::1 | 0.2ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 2 | ae0-2453.cr10.ber01.lwlcom.net 2a06:d1c0::dead:beef:1c02 | 0.6ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 3 | ae0-150.cr10.fra01.lwlcom.net 2a00:c380:b200:230::174 | 10.0ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 4 | ae6-3257.cr5-fra2.ip6.gtt.net 2001:668:0:3:ffff:1:0:3d5d | 9.5ms | 0% | AS3257 | GTT-BACKBONE - GTT Communications Inc., US |
| 5 | 2001:668:0:2:ffff:0:8d88:6e29 | 9.5ms | 0% | AS3257 | GTT-BACKBONE - GTT Communications Inc., US |
| 6 | 2001:41a8:600:2::1d5 | 31.5ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 7 | mil7-loop0-v6.mil.seabone.net 2001:41a8:20::7 | 28.6ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 8 | * | - | 80% | - | |
| 9 | * | - | - | - | |
| 10 | * | - | 0% | - | |
| 11 | 2a01:20f0:1010::3 | 29.8ms | 0% | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | 2001:4b18:a000::a | 25.6ms | 0% | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
Rate-limited ICMPv6: hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.014ms pmtu 1500
1: xe-0-0-13-178.gw01.ber01.as59645.net 0.518ms
1: xe-0-0-13-178.gw01.ber01.as59645.net 0.575ms
2: ae0-2453.cr10.ber01.lwlcom.net 0.928ms
3: ae0-150.cr10.fra01.lwlcom.net 10.223ms asymm 7
4: ae6-3257.cr5-fra2.ip6.gtt.net 9.980ms asymm 9
5: 2001:668:0:2:ffff:0:8d88:6e29 9.888ms asymm 10
6: 2001:41a8:600:2::1d5 10.730ms
7: mil7-loop0-v6.mil.seabone.net 47.599ms asymm 5
8: 2001:41a8:20:2::27a 28.069ms asymm 6
9: no reply
10: ??? 29.509ms asymm 8
11: ??? 30.274ms asymm 10
12: no reply
13: no reply
14: 2001:4b18:a000::a 25.896ms reached
Resume: pmtu 1500 hops 14 back 12 From DE host (Düsseldorf) icmp blocked
filter likely at: destination AS20746 (ASN-IDC) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | xe-0-0-12-142.gw01.dus01.as59645.net 2a06:d1c1:100:d::1 | 0.1ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 2 | eth1-0-12-h5594.edge5-dus1.bb.wiit.network 2001:4ba0:92f4:3::1 | 0.9ms | 0% | AS24961 | MYLOC-AS - WIIT AG, DE |
| 3 | lag13.agr3-dus3.bb.wiit.network 2001:4ba0:ffe9:7d::1 | 3.4ms | 0% | AS24961 | MYLOC-AS - WIIT AG, DE |
| 4 | lag11.core3-dus1.bb.wiit.network 2001:4ba0:ffe9:115::3 | 0.3ms | 0% | AS24961 | MYLOC-AS - WIIT AG, DE |
| 5 | * | - | 0% | - | |
| 6 | lo0.0.edge8.Frankfurt1.level3.net 2001:4c08::8e | 4.7ms | 0% | AS3356 | LEVEL3 - Level 3 Parent, LLC, US |
| 7 | 2001:41a8:600:2::3a1 | 4.2ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 8 | mil7-loop0-v6.mil.seabone.net 2001:41a8:20::7 | 13.6ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 9 | 2001:41a8:20:2::27a | 23.6ms | - | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 10 | * | - | - | - | |
| 11 | 2a01:20f0:1000::e | 21.4ms | - | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 12 | 2a01:20f0:1010::3 | 21.5ms | - | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | 2001:4b18:a000::a | 28.1ms | - | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
tracepath -6
1?: [LOCALHOST] 0.038ms pmtu 1500
1: xe-0-0-12-142.gw01.dus01.as59645.net 0.317ms
1: xe-0-0-12-142.gw01.dus01.as59645.net 0.386ms
2: eth1-0-12-h5594.edge5-dus1.bb.wiit.network 1.210ms
3: no reply
4: lag11.core3-dus1.bb.wiit.network 0.461ms
5: no reply
6: lo0.0.edge9.Frankfurt1.level3.net 22.872ms asymm 7
7: 3741-3356-frf.sp.lumen.tech 4.904ms asymm 5
8: mil7-loop0-v6.mil.seabone.net 13.937ms asymm 4
9: 2001:41a8:20:2::27a 14.974ms asymm 5
10: no reply
11: ??? 21.687ms asymm 7
12: ??? 24.235ms asymm 9
13: no reply
14: no reply
15: 2001:4b18:a000::a 20.241ms reached
Resume: pmtu 1500 hops 15 back 11 From NL host (go6lab) openRFC 4890 ✗
filter likely at: (none) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a00:8642:42::2 | 1.0ms | 0% | AS203993 | GNA-DC1-AS - S.J.M. Steffann, NL |
| 2 | * | - | 0%* | - | |
| 3 | 2a00:1ca8:1::194 | 4.3ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 4 | 2a03:3f40::10:41 | 5.6ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 5 | 2001:978:2:40::3:1 | 4.3ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 6 | be3457.ccr41.ams03.atlas.cogentco.com 2001:550:0:1000::8275:109 | 6.1ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 7 | be3499.rcr22.ams05.atlas.cogentco.com 2001:550:0:1000::9a36:3c16 | 6.1ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | 2001:978:3::a6 | 10.9ms | 60% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 9 | mil7-loop0-v6.mil.seabone.net 2001:41a8:20::7 | 26.4ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 10 | 2001:41a8:20:2::27a | 22.6ms | 60% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | 2a01:20f0:1010::3 | 31.2ms | - | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | 2001:4b18:a000::a | 24.6ms | - | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
Rate-limited ICMPv6: hop 8, hop 10 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.038ms pmtu 1500
1: 2a00:8642:42::2 5.617ms
1: 2a00:8642:42::2 3.279ms
2: no reply
3: 2a00:1ca8:1::194 5.652ms
4: 2a03:3f40::10:41 3.972ms
5: 2001:978:2:40::3:1 5.250ms
6: be3458.ccr42.ams03.atlas.cogentco.com 6.583ms
7: be3499.rcr22.ams05.atlas.cogentco.com 7.361ms
8: no reply
9: mil7-loop0-v6.mil.seabone.net 34.248ms asymm 8
10: 2001:41a8:20:2::27a 21.683ms asymm 9
11: no reply
12: ??? 25.144ms asymm 11
13: ??? 29.942ms
14: no reply
15: no reply
16: 2001:4b18:a000::a 25.888ms reached
Resume: pmtu 1500 hops 16 back 15 From ITA host (Karsolink) echo onlyRFC 4890 ✗
filter likely at: destination AS20746 (ASN-IDC) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | * | - | 0%* | - | |
| 2 | * | - | 0%* | - | |
| 3 | * | - | - | - | |
| 4 | 2a02:2d8:4:1815:232a | 3.5ms | 0% | - | |
| 5 | 2001:41a8:20:2::35 | 10.2ms | 10% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 6 | 2001:41a8:600:2::269 | 15.9ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 7 | mil7-loop0-v6.mil.seabone.net 2001:41a8:20::7 | 23.8ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 8 | 2001:41a8:20:2::27a | 18.4ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 9 | * | - | - | - | |
| 10 | 2a01:20f0:1000::e | 18.9ms | 0% | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 11 | * | - | 0% | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | 0% | - | |
| 15 | 2001:4b18:a000::a | 20.1ms | - | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
Rate-limited ICMPv6: hop 5 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.030ms pmtu 1500
1: karsolink-01.net.karsolink.com 0.601ms
2: 2a12:d8c0:109f:121::a1 0.490ms
3: no reply
4: ae8-202.rt.clr.mil.it.retn.net 7.850ms asymm 5
5: 2001:41a8:20:2::35 10.542ms
6: 2001:41a8:600:2::269 15.528ms
7: mil7-loop0-v6.mil.seabone.net 18.025ms asymm 6
8: no reply
9: ??? 12.771ms asymm 10
10: ??? 19.438ms
11: ??? 19.892ms asymm 12
12: no reply
13: no reply
14: 2001:4b18:a000::a 12.634ms reached
Resume: pmtu 1500 hops 14 back 14 From SLO host (6connect) openRFC 4890 ✗
filter likely at: (none) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | fw1-lju.6connect.com 2607:fae0:a000::2 | 0.2ms | 0%* | AS8038 | 6CONNECT - 6connect, Inc., US |
| 2 | * | - | - | - | |
| 3 | 2a00:ee1:800:9::1 | 1.7ms | 60% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 4 | 2a00:ee0:1:15::2 | 1.0ms | 0% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 5 | 2001:41a8:20:2::169 | 11.0ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 6 | mil51-loop0-v6.mil.seabone.net 2001:41a8:20::33 | 9.3ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 7 | 2001:41a8:20:2::412 | 9.5ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 8 | * | - | - | - | |
| 9 | 2a01:20f0:1000::e | 9.4ms | 0% | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 10 | * | - | 0% | - | |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | 2001:4b18:a000::a | 16.4ms | 0% | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.023ms pmtu 9000
1: fw1-lju.6connect.com 0.625ms
1: fw1-lju.6connect.com 0.535ms
2: no reply
3: 2a00:ee1:800:9::1 2.175ms
4: 2a00:ee0:1:15::2 1.640ms asymm 3
5: 2a00:ee0:1:15::2 1.726ms pmtu 1500
5: 2001:41a8:20:2::169 9.178ms asymm 6
6: mil51-loop0-v6.mil.seabone.net 9.332ms
7: 2001:41a8:20:2::412 10.204ms asymm 6
8: no reply
9: ??? 10.288ms asymm 8
10: ??? 10.670ms
11: no reply
12: no reply
13: 2001:4b18:a000::a 10.152ms reached
Resume: pmtu 1500 hops 13 back 13 From SLO host (T-2) openRFC 4890 ✗
filter likely at: (none) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | * | - | 0%* | - | |
| 2 | 2a01:260:1::225 | 2.4ms | 0%* | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 3 | 2a01-260-1-1--9a.core6.t-2.net 2a01:260:1:1::9a | 2.3ms | 0%* | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 4 | 2a01-260-1-1--39.core6.t-2.net 2a01:260:1:1::39 | 1.8ms | 10% | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 5 | hurricane-electric.nikhef.nlsix.net 2001:7f8:13::a500:6939:1 | 36.1ms | - | - | NA |
| 6 | be6.core3.par2.he.net 2001:470:0:349::1 | 40.0ms | 40% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | seabone-net-as6762.port-channel7.core2.par2.he.net 2001:470:0:2f6::2 | 38.4ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 8 | seabone-net-as6762.port-channel7.core2.par2.he.net 2001:470:0:2f6::2 | 38.3ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 9 | mil7-loop0-v6.mil.seabone.net 2001:41a8:20::7 | 35.7ms | 30% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 10 | 2001:41a8:20:2::27a | 37.5ms | - | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 11 | 2a01:20f0:1000::e | 36.2ms | - | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 12 | 2a01:20f0:1000::e | 34.7ms | - | AS3269 | ASN-IBSNAZ - Telecom Italia S.p.A., IT |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | 2001:4b18:a000::a | 36.3ms | - | AS20746 | ASN-IDC - Telecom Italia S.p.A., IT |
Rate-limited ICMPv6: hop 4, hop 6, hop 9 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.046ms pmtu 1500
1: 2a01:261:313:b814::1 0.863ms
1: 2a01:261:313:b814::1 0.811ms
2: 2a01:260:1::225 2.655ms
3: 2a01-260-1-1--9c.core6.t-2.net 3.139ms
4: 2a01-260-1-1--39.core6.t-2.net 2.396ms asymm 3
5: hurricane-electric.nikhef.nlsix.net 34.092ms asymm 4
6: be6.core3.par2.he.net 39.201ms
7: be6.core3.par2.he.net 40.385ms asymm 6
8: mil7-loop0-v6.mil.seabone.net 41.068ms asymm 7
9: mil7-loop0-v6.mil.seabone.net 35.117ms asymm 7
10: 2001:41a8:20:2::27a 36.426ms asymm 8
11: no reply
12: ??? 36.472ms asymm 10
13: ??? 36.665ms asymm 12
14: no reply
15: no reply
16: 2001:4b18:a000::a 55.410ms reached
Resume: pmtu 1500 hops 16 back 14