AS overview
Test target: 2a02:4140:0:1002::52 · ns1.wnt.at · address space: mixed · prefixes announced: 2
prefix(es): 2a02:4140::/32, 2a00:b220::/32
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 / 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 | ||
2a02:4140:0:1002::52ns1.wnt.at | NS | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | ? | ? | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | - |
2a02:4140:0:1003::52ns2.wnt.at | NS | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | ? | ? | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | - |
RPKI & ASPA
2 of 2 prefix(es) covered by a valid ROA.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a02:4140::/32 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS43957 /32 maxLen 32 (ripe) |
2a00:b220::/32 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS43957 /32 maxLen 32 (ripe) |
Random-IP probe (yarrp) into the AS' prefixes
We probed 70 arbitrary IPv6 address(es) inside AS43957's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a01:4a0:1338:25::2 at hop 12 - that router answers ICMPv6 Echo. This is not in AS43957'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): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
- DE host (Berlin): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
- DE host (Düsseldorf): Type 2 honored. Forged PTB accepted; next response shrunk. (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 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
- SLO host (6connect): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
- SLO host (T-2): Type 2 honored. Forged PTB accepted; next response shrunk. (ICMPv6 Echo + forged PTB)
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
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| belgrade | 2a09:ab81::91 | 2a02:4140:0:1002::52 | icmp6-echo | honored | 2026-09-23T13:34:27Z |
| berlin | 2a06:d1c1:10b::cccc | 2a02:4140:0:1002::52 | icmp6-echo | honored | 2026-09-23T13:34:27Z |
| duseldorf | 2a06:d1c1:10d::aaaa | 2a02:4140:0:1002::52 | icmp6-echo | honored | 2026-09-23T13:34:29Z |
| go6lab | 2a00:8642:42::75 | 2a02:4140:0:1002::52 | icmp6-echo | not_honored | 2026-09-23T13:35:03Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a02:4140:0:1002::52 | icmp6-echo | honored | 2026-09-23T13:34:20Z |
| odin | 2607:fae0:a000::42 | 2a02:4140:0:1002::52 | icmp6-echo | honored | 2026-09-23T13:34:31Z |
| t2 | 2a01:261:313:b814:2a0:98ff:fe5b:13e4 | 2a02:4140:0:1002::52 | icmp6-echo | honored | 2026-09-23T13:34:26Z |
Attempt log (belgrade):
icmp6-echo→ honored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (berlin):
icmp6-echo→ honored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (duseldorf):
icmp6-echo→ honored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (go6lab):
icmp6-echo→ not_honored (reply shrank 1360→1360 B)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (karsolink):
icmp6-echo→ honored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (odin):
icmp6-echo→ honored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (t2):
icmp6-echo→ honored (honored by fragmenting its reply into 2 via the IPv6 Fragment Header, rather than resizing)dns-tcp→ inconclusive (reply 156 B before PTB): max DNS-over-TCP segment 156B; not big enough to test PMTU shrinktls→ 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 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
- 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 (2026-09-23T13:35:03Z) 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→ verdicthonored - berlin: probe
icmp6-echo→ verdicthonored - duseldorf: probe
icmp6-echo→ verdicthonored - go6lab: probe
icmp6-echo→ verdictnot_honored - karsolink: probe
icmp6-echo→ verdicthonored - odin: probe
icmp6-echo→ verdicthonored - t2: probe
icmp6-echo→ verdicthonored
Full per-method matrix (all four methods run at each vantage):
| vantage | icmp6-echo | dns-tcp | tls | http |
|---|---|---|---|---|
| belgrade | honored | inconclusive | no_tcp | no_tcp |
| berlin | honored | inconclusive | no_tcp | no_tcp |
| duseldorf | honored | inconclusive | no_tcp | no_tcp |
| go6lab | not_honored | inconclusive | no_tcp | no_tcp |
| karsolink | honored | inconclusive | no_tcp | no_tcp |
| odin | honored | inconclusive | no_tcp | no_tcp |
| t2 | honored | inconclusive | no_tcp | no_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): AS43957, AS6939, AS201011.
- From belgrade (open/Type-2=honored) the path enters an opaque hop at hop 13; from berlin (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (open/Type-2=honored) the path enters an opaque hop at hop 7; from duseldorf (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (open/Type-2=honored) the path enters AS43957 at hop 5; from go6lab (open/Type-2=not_honored) the same hop is in AS6939. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (open/Type-2=honored) the path enters an opaque hop at hop 7; from karsolink (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (open/Type-2=honored) the path enters AS43957 at hop 5; from odin (open/Type-2=honored) the same hop is in AS6939. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (open/Type-2=honored) the path enters an opaque hop at hop 7; from t2 (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS201011 at hop 8; from duseldorf (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS201011 at hop 8; from go6lab (open/Type-2=not_honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS201011 at hop 8; from karsolink (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS201011 at hop 8; from odin (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS201011 at hop 8; from t2 (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (open/Type-2=honored) the path enters an opaque hop at hop 5; from go6lab (open/Type-2=not_honored) the same hop is in AS6939. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (open/Type-2=honored) the path enters an opaque hop at hop 5; from odin (open/Type-2=honored) the same hop is in AS6939. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=not_honored) the path enters AS6939 at hop 7; from karsolink (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=not_honored) the path enters AS6939 at hop 7; from odin (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=not_honored) the path enters AS6939 at hop 7; from t2 (open/Type-2=honored) the same hop is in AS43957. Last common AS: AS43957. 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
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 2a02:4140:0:1002::52
amsterdam - verdict ?
(no hops captured)
belgrade - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2001:7f8:1e:8::3a | |
| 3 | 2001:7f8:1e:8::3d | |
| 4 | 2001:67c:128c::699 | |
| 5 | 2a02:4140:0:1002::52 |
berlin - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a06:d1c0::dead:beef:1c02 | |
| 3 | 2a00:c380:b200:230::192 | |
| 4 | 2a00:c380:b200:230::45 | |
| 5 | 2a00:c380:f000::4b | |
| 6 | 2a01:4a0:0:2087::33 | |
| 7 | 2a01:4a0:0:2026::1 | |
| 8 | 2a01:4a0:0:2123::42 | |
| 9 | 2a01:4a0:0:2027::6 | |
| 10 | 2a01:4a0:0:2030::7 | |
| 11 | 2a01:4a0:0:2028::10 | |
| 12 | 2a01:4a0:1338:25::2 | |
| 13 | 2a02:4140:0:1::25 | |
| 14 | 2a02:4140:0:1002::52 |
duseldorf - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2001:7f8:9e::1b1b:0:1 | |
| 3 | 2001:470:0:52e::1 | |
| 4 | 2001:470:e:1e::2 | |
| 5 | 2001:470:e:a7::2 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2a02:4140:0:1::25 | |
| 8 | 2a02:4140:0:1002::52 |
go6lab - verdict not_honored
verdict = not_honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a00:8642:1000:f000::1 | |
| 3 | 2001:7f8:b7::a500:6939:1 | |
| 4 | 2001:470:e:38::2 | |
| 5 | 2001:470:e:1e::2 | |
| 6 | 2001:470:e:a7::2 | |
| 7 | 2001:470:34a::2 | |
| 8 | 2a02:4140:0:1::25 | |
| 9 | 2a02:4140:0:1002::52 |
karsolink - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a12:d8c0:109f:121::a1 | |
| 3 | 2a12:d8c0:101f:6::1 | |
| 4 | <span class='muted'>no reply</span> | |
| 5 | 2001:470:0:414::1 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2a02:4140:0:1::25 | |
| 8 | 2a02:4140:0:1002::52 |
odin - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2607:fae0:a000:2::2 | |
| 3 | 2a03:a100:0:201:1::1 | |
| 4 | 2a03:a100:0:201:1::1 | |
| 5 | 2001:470:0:578::1 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2a02:4140:0:1::25 | |
| 8 | 2a02:4140:0:1002::52 |
t2 - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a01:260:1::225 | |
| 3 | 2a01:260:1:1::9a | |
| 4 | 2a01:260:1:1::38 | |
| 5 | 2001:470:0:4a8::1 | |
| 6 | 2001:470:0:4a8::1 | |
| 7 | 2a02:4140:0:1::25 | |
| 8 | 2a02:4140:0:1002::52 |
Target 2a02:4140:0:1003::52
amsterdam - verdict ?
(no hops captured)
belgrade - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2001:7f8:1e:8::3a | |
| 3 | 2001:7f8:1e:8::3d | |
| 4 | 2001:67c:128c::699 | |
| 5 | 2a02:4140:0:1003::52 |
berlin - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a06:d1c0::dead:beef:1c02 | |
| 3 | 2a00:c380:b200:230::192 | |
| 4 | 2a00:c380:b200:230::45 | |
| 5 | 2a00:c380:f000::4b | |
| 6 | 2a01:4a0:0:2087::33 | |
| 7 | 2a01:4a0:0:2026::1 | |
| 8 | 2a01:4a0:0:2123::42 | |
| 9 | 2a01:4a0:0:2027::6 | |
| 10 | 2a01:4a0:0:2030::7 | |
| 11 | 2a01:4a0:0:2028::10 | |
| 12 | 2a01:4a0:1338:25::2 | |
| 13 | 2a02:4140:0:1::45 | |
| 14 | 2a02:4140:0:1003::52 |
duseldorf - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2001:7f8:9e::1b1b:0:1 | |
| 3 | 2001:470:0:52e::1 | |
| 4 | 2001:470:e:1e::2 | |
| 5 | 2001:470:e:a7::2 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2a02:4140:0:1::45 | |
| 8 | 2a02:4140:0:1003::52 |
go6lab - verdict not_honored
verdict = not_honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a00:8642:1000:f000::1 | |
| 3 | 2001:7f8:b7::a500:6939:1 | |
| 4 | 2001:470:e:38::2 | |
| 5 | 2001:470:e:1e::2 | |
| 6 | 2001:470:e:a7::2 | |
| 7 | 2001:470:34a::2 | |
| 8 | 2a02:4140:0:1::45 | |
| 9 | 2a02:4140:0:1003::52 |
karsolink - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a12:d8c0:109f:121::a1 | |
| 3 | 2a12:d8c0:101f:6::1 | |
| 4 | <span class='muted'>no reply</span> | |
| 5 | 2001:470:0:414::1 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2a02:4140:0:1::45 | |
| 8 | 2a02:4140:0:1003::52 |
odin - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2607:fae0:a000:2::2 | |
| 3 | 2a03:a100:0:201:1::1 | |
| 4 | 2a03:a100:0:201:1::1 | |
| 5 | 2001:470:0:578::1 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2a02:4140:0:1::45 | |
| 8 | 2a02:4140:0:1003::52 |
t2 - verdict honored
verdict = honored; final pmtu = 1500
| # | hop IP | pmtu change |
|---|---|---|
| 1 | <span class='muted'>no reply</span> | |
| 2 | 2a01:260:1::225 | |
| 3 | 2a01:260:1:1::9a | |
| 4 | 2a01:260:1:1::38 | |
| 5 | 2001:470:0:4a8::1 | |
| 6 | 2001:470:34a::2 | |
| 7 | 2001:470:34a::2 | |
| 8 | 2a02:4140:0:1::45 | |
| 9 | 2a02:4140:0:1003::52 |
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) openRFC 4890 ✓
filter likely at: (none) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a09:ab81::1 | 0.3ms | 0%* | AS60733 | PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS |
| 2 | sox-pn.sox.rs 2001:7f8:1e:8::3a | 0.3ms | 0% | AS13004 | SOX - Serbian Open Exchange DOO, RS |
| 3 | 2001:7f8:1e:8::3d | 0.3ms | 0% | AS13004 | SOX - Serbian Open Exchange DOO, RS |
| 4 | 2001:67c:128c::699 | 18.0ms | 0% | - | NA |
| 5 | ns1.wnt.at 2a02:4140:0:1002::52 | 34.7ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
tracepath -6
1?: [LOCALHOST] 0.013ms pmtu 1500
1: _gateway 0.447ms
1: _gateway 0.534ms
2: sox-pn.sox.rs 0.572ms
3: 2001:7f8:1e:8::3d 0.657ms asymm 2
4: 2001:67c:128c::699 16.478ms
5: ns1.wnt.at 35.875ms reached
Resume: pmtu 1500 hops 5 back 8 From DE host (Berlin) openRFC 4890 ✓
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 | 0.3ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 2 | ae0-2453.cr10.ber01.lwlcom.net 2a06:d1c0::dead:beef:1c02 | 0.8ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 3 | ae3-90.cr10.ham01.lwlcom.net 2a00:c380:b200:230::192 | 5.0ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 4 | ae0-50.cr11.ham01.lwlcom.net 2a00:c380:b200:230::45 | 5.0ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 5 | 2a00:c380:f000::4b | 5.2ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 6 | ae4-2087.dus10.core-backbone.com 2a01:4a0:0:2087::33 | 11.3ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 7 | ae43-2026.fra30.core-backbone.com 2a01:4a0:0:2026::1 | 11.2ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 8 | ae16-2123.fra40.core-backbone.com 2a01:4a0:0:2123::42 | 11.1ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 9 | ae8-2027.muc10.core-backbone.com 2a01:4a0:0:2027::6 | 15.2ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 10 | ae1-2030.muc20.core-backbone.com 2a01:4a0:0:2030::7 | 15.2ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 11 | ae1-2028.vie10.core-backbone.com 2a01:4a0:0:2028::10 | 20.8ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 12 | 2a01:4a0:1338:25::2 | 21.3ms | 0% | AS201011 | CORE-BACKBONE - Core-Backbone GmbH, DE |
| 13 | 2a02:4140:0:1::25 | 24.7ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
| 14 | ns1.wnt.at 2a02:4140:0:1002::52 | 25.0ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
tracepath -6
1?: [LOCALHOST] 0.036ms pmtu 1500
1: xe-0-0-13-178.gw01.ber01.as59645.net 0.674ms
1: xe-0-0-13-178.gw01.ber01.as59645.net 0.591ms
2: ae0-2453.cr10.ber01.lwlcom.net 1.111ms
3: ae3-90.cr10.ham01.lwlcom.net 5.234ms
4: ae0-50.cr11.ham01.lwlcom.net 5.362ms
5: 2a00:c380:f000::4b 5.638ms asymm 4
6: ae4-2087.dus10.core-backbone.com 11.891ms asymm 5
7: ae43-2026.fra30.core-backbone.com 11.501ms asymm 5
8: ae16-2123.fra40.core-backbone.com 11.517ms asymm 6
9: ae8-2027.muc10.core-backbone.com 15.466ms asymm 8
10: ae1-2030.muc20.core-backbone.com 15.723ms asymm 7
11: ae1-2028.vie10.core-backbone.com 21.245ms asymm 8
12: 2a01:4a0:1338:25::2 22.517ms asymm 5
13: 2a02:4140:0:1::25 25.071ms asymm 7
14: ns1.wnt.at 25.657ms reached
Resume: pmtu 1500 hops 14 back 8 From DE host (Düsseldorf) openRFC 4890 ✓
filter likely at: (none) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | xe-0-0-12-142.gw01.dus01.as59645.net 2a06:d1c1:100:d::1 | 0.2ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 2 | ipv6.decix-dusseldorf.core1.dus1.he.net 2001:7f8:9e::1b1b:0:1 | 6.1ms | 0% | - | NA |
| 3 | * | - | 50% | - | |
| 4 | be8.core1.prg1.he.net 2001:470:e:1e::2 | 11.6ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 5 | * | - | 60% | - | |
| 6 | 2001:470:34a::2 | 15.1ms | 10% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2a02:4140:0:1::25 | 15.3ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
| 8 | ns1.wnt.at 2a02:4140:0:1002::52 | 15.6ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
Rate-limited ICMPv6: hop 3, hop 5, hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.026ms pmtu 1500
1: xe-0-0-12-142.gw01.dus01.as59645.net 0.379ms
1: xe-0-0-12-142.gw01.dus01.as59645.net 0.349ms
2: ipv6.decix-dusseldorf.core1.dus1.he.net 6.793ms asymm 3
3: 100ge0-0-0-18.core4.fra1.he.net 8.375ms asymm 4
4: be8.core1.prg1.he.net 14.371ms asymm 5
5: be3.core1.vie1.he.net 18.489ms asymm 4
6: 2001:470:34a::2 15.511ms asymm 5
7: 2a02:4140:0:1::25 15.579ms asymm 6
8: ns1.wnt.at 16.132ms reached
Resume: pmtu 1500 hops 8 back 7 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 | 1.4ms | 0% | AS203993 | GNA-DC1-AS - S.J.M. Steffann, NL |
| 2 | gw.friends.steffann.nl 2a00:8642:1000:f000::1 | 5.3ms | 0%* | AS203993 | GNA-DC1-AS - S.J.M. Steffann, NL |
| 3 | speed-ix.he.net 2001:7f8:b7::a500:6939:1 | 5.6ms | 0% | - | NA |
| 4 | be2.core4.fra1.he.net 2001:470:e:38::2 | 14.5ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 5 | be8.core1.prg1.he.net 2001:470:e:1e::2 | 17.9ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 6 | be3.core1.vie1.he.net 2001:470:e:a7::2 | 20.7ms | 70% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2001:470:34a::2 | 20.5ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 8 | 2a02:4140:0:1::25 | 19.9ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
| 9 | ns1.wnt.at 2a02:4140:0:1002::52 | 20.5ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
Rate-limited ICMPv6: hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.030ms pmtu 1500
1: 2a00:8642:42::2 4.018ms
1: 2a00:8642:42::2 1.569ms
2: gw.friends.steffann.nl 2.227ms
3: speed-ix.he.net 8.037ms
4: be2.core4.fra1.he.net 12.453ms
5: be8.core1.prg1.he.net 19.113ms
6: be3.core1.vie1.he.net 26.838ms
7: 2001:470:34a::2 21.984ms
8: 2a02:4140:0:1::25 21.812ms
9: ns1.wnt.at 22.400ms reached
Resume: pmtu 1500 hops 9 back 9 From ITA host (Karsolink) 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 | 2a12:d8c0:109f:121::a1 | 0.4ms | - | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 3 | * | - | 0% | - | |
| 4 | * | - | - | - | |
| 5 | * | - | 60% | - | |
| 6 | 2001:470:34a::2 | 63.2ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2a02:4140:0:1::25 | 51.2ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
| 8 | ns1.wnt.at 2a02:4140:0:1002::52 | 30.8ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
Rate-limited ICMPv6: hop 5 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.028ms pmtu 1500
1: karsolink-01.net.karsolink.com 0.893ms
1: karsolink-01.net.karsolink.com 1.605ms
2: 2a12:d8c0:109f:121::a1 0.982ms
3: 2a12:d8c0:101f:103::1 9.184ms
4: no reply
5: 100ge0-0-0-20.core1.vie1.he.net 23.561ms
6: 2001:470:34a::2 22.193ms
7: 2a02:4140:0:1::25 21.451ms
8: ns1.wnt.at 20.718ms reached
Resume: pmtu 1500 hops 8 back 8 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 | 0.5ms | 0%* | AS8038 | 6CONNECT - 6connect, Inc., US |
| 2 | * | - | - | - | |
| 3 | 2a03:a100:0:201:1::1 | 0.8ms | 0% | AS56635 | XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI |
| 4 | e0-1.core1.lju1.he.net 2001:470:1:5be::1 | 2.2ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 5 | 100ge0-0-0-5.core1.vie1.he.net 2001:470:0:578::1 | 8.3ms | 20% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 6 | 2001:470:34a::2 | 10.2ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2a02:4140:0:1::25 | 6.4ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
| 8 | ns1.wnt.at 2a02:4140:0:1002::52 | 6.8ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
Rate-limited ICMPv6: hop 5 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.017ms pmtu 9000
1: fw1-lju.6connect.com 0.629ms
1: fw1-lju.6connect.com 0.566ms
2: no reply
3: 2a03:a100:0:201:1::1 0.959ms
4: 2a03:a100:0:201:1::1 0.925ms pmtu 1500
4: e0-1.core1.lju1.he.net 2.174ms
5: 100ge0-0-0-5.core1.vie1.he.net 9.099ms
6: 2001:470:34a::2 7.760ms
7: 2a02:4140:0:1::25 6.768ms
8: ns1.wnt.at 6.931ms reached
Resume: pmtu 1500 hops 8 back 8 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 | 2.6ms | 0%* | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 3 | 2a01-260-1-1--9c.core6.t-2.net 2a01:260:1:1::9c | 1.8ms | 0%* | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 4 | * | - | - | - | |
| 5 | * | - | 30% | - | |
| 6 | 2001:470:34a::2 | 9.6ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2a02:4140:0:1::25 | 9.8ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
| 8 | 2a02:4140:0:1::25 | 9.8ms | 0% | AS43957 | ASN-WNTNEWMEDIA - WNT Telecommunication GmbH, AT |
Rate-limited ICMPv6: hop 5 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.033ms pmtu 1500
1: 2a01:261:313:b814::1 0.849ms
1: no reply
2: 2a01:260:1::225 4.454ms
3: 2a01-260-1-1--9a.core6.t-2.net 3.096ms
4: 2a01-260-1-1--38.core6.t-2.net 3.011ms asymm 3
5: no reply
6: 2001:470:34a::2 70.650ms asymm 7
7: 2001:470:34a::2 10.454ms
8: 2a02:4140:0:1::25 11.138ms
9: ??? 10.358ms reached
Resume: pmtu 1500 hops 9 back 9