AS overview
Test target: 2001:4100:0:64::28 · www.internic.at · address space: mixed · prefixes announced: 1
prefix(es): 2001:4100::/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 | ||
2001:4100:0:64::28www.internic.at | drv | ✓ | ✓ | open | open | ✓ | ✓ | ✓ | open | open | ✓ | ✓ | ✓ | open | open | ✓ | ✓ | ✓ | open | open | ✓ | ✓ | ✓ | open | open | ✓ | ✓ | ✓ | open | open | ✓ | ✓ | ✓ | open | open | - |
2001:4100:0:64::65:198www2.internic.at | drv | ✓ | ✓ | refused | open | ✓ | ✓ | ✓ | refused | open | ✓ | ✓ | ✓ | refused | open | ✓ | ✓ | ✓ | ? | open | ✓ | ✓ | ✓ | refused | open | ✓ | ✓ | ✓ | refused | open | ✓ | ✓ | ✓ | refused | open | ✓ |
VIX / AAIX / SAIX / TIROL-IX / ERA-IX peering
Not an VIX / AAIX / SAIX / TIROL-IX / ERA-IX member, but our traceroute path crosses the VIX / AAIX / SAIX / TIROL-IX / ERA-IX LAN from SRB host (SOX, Belgrade), DE host (Berlin), DE host (Düsseldorf), NL host (go6lab), ITA host (Karsolink), SLO host (6connect), SLO host (T-2) - reached via an VIX / AAIX / SAIX / TIROL-IX / ERA-IX-resident transit operator.
RPKI & ASPA
0 of 1 prefix(es) covered by a valid ROA, 1 not-found.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2001:4100::/32 | - not-found | no covering VRP |
Random-IP probe (yarrp) into the AS' prefixes
We probed 35 arbitrary IPv6 address(es) inside AS12401's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:7f8:30:0:2:1:1:2401 at hop 22 - that router answers ICMPv6 Echo. This is not in AS12401'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
Type 2 honored. Forged ICMPv6 PTB (MTU=1280) was accepted by the destination's stack: the next 1500-byte Echo Reply arrived split into 2 fragments via the IPv6 Fragment Header.
method: ICMPv6 Echo + forged PTB, tested 2026-09-22T13:49:07Z
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→ verdicthonored - 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 | no_tcp | partial | inconclusive |
| berlin | honored | no_tcp | partial | inconclusive |
| duseldorf | honored | no_tcp | not_honored | inconclusive |
| go6lab | honored | no_tcp | not_honored | inconclusive |
| karsolink | honored | no_tcp | partial | inconclusive |
| odin | honored | no_tcp | partial | inconclusive |
| t2 | honored | no_tcp | not_honored | inconclusive |
✓ 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): AS12401, AS50629, AS6939.
- From belgrade (open/Type-2=honored) the path enters AS12401 at hop 6; from duseldorf (open/Type-2=honored) the same hop is in AS50629. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From belgrade (open/Type-2=honored) the path enters AS12401 at hop 6; from go6lab (open/Type-2=honored) the same hop is in AS6939. Last common AS: AS12401. 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 AS12401. Last common AS: AS12401. 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 odin (open/Type-2=honored) the same hop is in AS12401. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS12401 at hop 6; from duseldorf (open/Type-2=honored) the same hop is in AS50629. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters AS12401 at hop 6; from go6lab (open/Type-2=honored) the same hop is in AS6939. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters an opaque hop at hop 7; from karsolink (open/Type-2=honored) the same hop is in AS12401. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From berlin (open/Type-2=honored) the path enters an opaque hop at hop 7; from odin (open/Type-2=honored) the same hop is in AS12401. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (open/Type-2=honored) the path enters AS50629 at hop 4; from go6lab (open/Type-2=honored) the same hop is in AS6939. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (open/Type-2=honored) the path enters AS50629 at hop 7; from karsolink (open/Type-2=honored) the same hop is in AS12401. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From duseldorf (open/Type-2=honored) the path enters AS50629 at hop 3; from odin (open/Type-2=honored) the same hop is in AS56635. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=honored) the path enters AS12401 at hop 8; from karsolink (open/Type-2=honored) the same hop is in an opaque hop. Last common AS: AS12401. The disagreement is most likely rooted in one of those two transit ASes.
- From go6lab (open/Type-2=honored) the path enters AS6939 at hop 6; from odin (open/Type-2=honored) the same hop is in an opaque hop. Last common AS: AS12401. 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) 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 | 0.4ms | 0%* | AS60733 | PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS |
| 2 | sox-pn.sox.rs 2001:7f8:1e:8::3a | 0.2ms | 0% | AS13004 | SOX - Serbian Open Exchange DOO, RS |
| 3 | 2001:7f8:1e:8::3d | 0.6ms | 0% | AS13004 | SOX - Serbian Open Exchange DOO, RS |
| 4 | 2a02:2d8:0:a00e:232a | 12.6ms | 10% | - | |
| 5 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 11.1ms | 0% | - | NA |
| 6 | 2001:4100:0:64::28 | 11.1ms | 0% | AS12401 | INTERNIC-AS12401 - internic Datenkommunikations GmbH, AT |
Rate-limited ICMPv6: hop 4 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.010ms pmtu 1500
1: _gateway 0.662ms
1: _gateway 1.800ms
2: sox-pn.sox.rs 1.146ms
3: 2001:7f8:1e:8::3d 2.535ms asymm 2
4: ae8-930.RT.IRX.VIE.AT.retn.net 13.394ms asymm 3
5: 2001:7f8:30:0:2:1:1:2401 13.033ms asymm 3
6: 2001:4100:0:64::28 11.192ms reached
Resume: pmtu 1500 hops 6 back 4 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 | 0.2ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 2 | ae0-2453.cr10.ber01.lwlcom.net 2a06:d1c0::dead:beef:1c02 | 0.7ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 3 | ae0-40.cr10.muc02.lwlcom.net 2a00:c380:b200:230::178 | 11.2ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 4 | ae0-10.cr10.muc01.lwlcom.net 2a00:c380:b200:230::177 | 11.4ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 5 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 17.3ms | 0% | - | NA |
| 6 | 2001:4100:0:64::28 | 17.3ms | 0% | AS12401 | INTERNIC-AS12401 - internic Datenkommunikations GmbH, AT |
tracepath -6
1?: [LOCALHOST] 0.030ms pmtu 1500
1: xe-0-0-13-178.gw01.ber01.as59645.net 1.146ms
1: xe-0-0-13-178.gw01.ber01.as59645.net 1.246ms
2: ae0-2453.cr10.ber01.lwlcom.net 1.325ms
3: ae0-40.cr10.muc02.lwlcom.net 12.534ms
4: ae0-10.cr10.muc01.lwlcom.net 11.844ms
5: 2001:7f8:30:0:2:1:1:2401 17.978ms
6: 2001:4100:0:64::28 18.012ms reached
Resume: pmtu 1500 hops 6 back 6 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 | 0.1ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 2 | ae0-101.cr10.dus02.lwlcom.net 2a06:d1c0::dead:beef:1301 | 0.2ms | 0%* | AS59645 | WYBT-NET - Tobias Fiebig, DE |
| 3 | ae0-40.cr10.dus05.lwlcom.net 2a00:c380:b200:230::199 | 0.3ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 4 | ae0-20.cr10.vel01.lwlcom.net 2a00:c380:b200:230::65 | 1.1ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 5 | ae0-10.cr10.dus06.lwlcom.net 2a00:c380:b200:230::147 | 0.6ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 6 | ae0-40.cr10.fra06.lwlcom.net 2a00:c380:b200:230::21 | 3.9ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 7 | ae0-20.cr10.muc01.lwlcom.net 2a00:c380:b200:230::250 | 14.7ms | 0% | AS50629 | LWLCOM - LWLcom GmbH, DE |
| 8 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 20.3ms | 0% | - | NA |
| 9 | 2001:4100:0:64::28 | 20.7ms | 0% | AS12401 | INTERNIC-AS12401 - internic Datenkommunikations GmbH, AT |
tracepath -6
1?: [LOCALHOST] 0.015ms pmtu 1500
1: xe-0-0-12-142.gw01.dus01.as59645.net 0.478ms
1: xe-0-0-12-142.gw01.dus01.as59645.net 0.946ms
2: ae0-101.cr10.dus02.lwlcom.net 0.669ms
3: ae0-20.cr10.dus01.lwlcom.net 1.168ms
4: ae0-90.cr11.dus01.lwlcom.net 1.101ms
5: ae0-30.cr10.dus06.lwlcom.net 1.572ms
6: ae0-40.cr10.fra06.lwlcom.net 4.091ms
7: ae0-20.cr10.muc01.lwlcom.net 14.869ms asymm 5
8: 2001:7f8:30:0:2:1:1:2401 20.496ms asymm 6
9: 2001:4100:0:64::28 21.267ms reached
Resume: pmtu 1500 hops 9 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 | 2.5ms | 0% | AS203993 | GNA-DC1-AS - S.J.M. Steffann, NL |
| 2 | * | - | 0%* | - | |
| 3 | speed-ix.he.net 2001:7f8:b7::a500:6939:1 | 8.5ms | 10% | - | NA |
| 4 | be2.core4.fra1.he.net 2001:470:e:38::2 | 12.4ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 5 | be8.core1.prg1.he.net 2001:470:e:1e::2 | 18.8ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 6 | be3.core1.vie1.he.net 2001:470:e:a7::2 | 21.6ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 49.1ms | 0% | - | NA |
| 8 | 2001:4100:0:64::28 | 21.7ms | 0% | AS12401 | INTERNIC-AS12401 - internic Datenkommunikations GmbH, AT |
Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.035ms pmtu 1500
1: 2a00:8642:42::2 2.122ms
1: 2a00:8642:42::2 3.030ms
2: no reply
3: speed-ix.he.net 5.987ms
4: be2.core4.fra1.he.net 11.921ms
5: be8.core1.prg1.he.net 19.712ms
6: be3.core1.vie1.he.net 23.464ms
7: 2001:7f8:30:0:2:1:1:2401 23.748ms
8: 2001:4100:0:64::28 23.917ms reached
Resume: pmtu 1500 hops 8 back 8 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 | * | - | 0%* | - | |
| 3 | * | - | 70% | - | |
| 4 | * | - | - | - | |
| 5 | 100ge0-0-0-20.core1.vie1.he.net 2001:470:0:414::1 | 21.6ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 6 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 16.0ms | 0% | - | NA |
| 7 | 2001:4100:0:64::28 | 15.9ms | 0% | AS12401 | INTERNIC-AS12401 - internic Datenkommunikations GmbH, AT |
Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.029ms pmtu 1500
1: karsolink-01.net.karsolink.com 1.262ms
1: karsolink-01.net.karsolink.com 1.337ms
2: 2a12:d8c0:109f:121::a1 1.296ms
3: 2a12:d8c0:101f:6::1 10.654ms
4: no reply
5: 100ge0-0-0-20.core1.vie1.he.net 22.052ms
6: 2001:7f8:30:0:2:1:1:2401 15.815ms
7: 2001:4100:0:64::28 16.507ms reached
Resume: pmtu 1500 hops 7 back 7 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 | * | - | 0%* | - | |
| 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 | 2.0ms | 20% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 5 | 100ge0-0-0-5.core1.vie1.he.net 2001:470:0:578::1 | 8.5ms | 60% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 6 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 7.3ms | 0% | - | NA |
| 7 | 2001:4100:0:64::28 | 7.2ms | 0% | AS12401 | INTERNIC-AS12401 - internic Datenkommunikations GmbH, AT |
Rate-limited ICMPv6: hop 4, hop 5 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.018ms pmtu 9000
1: fw1-lju.6connect.com 0.742ms
1: fw1-lju.6connect.com 0.843ms
2: ccr-to-fw-ccr1-gw-lju.6connect.com 1.047ms
3: 2a03:a100:0:201:1::1 1.001ms
4: 2a03:a100:0:201:1::1 1.062ms pmtu 1500
4: e0-1.core1.lju1.he.net 2.573ms
5: 100ge0-0-0-5.core1.vie1.he.net 8.336ms
6: 2001:7f8:30:0:2:1:1:2401 7.254ms asymm 5
7: 2001:4100:0:64::28 7.662ms reached
Resume: pmtu 1500 hops 7 back 5 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 | 8.3ms | 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 | 2.4ms | 0%* | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 4 | 2a01-260-1-1--38.core6.t-2.net 2a01:260:1:1::38 | 2.5ms | - | AS34779 | T-2-AS - T-2, d.o.o., SI |
| 5 | * | - | 0% | - | |
| 6 | 100ge0-0-0-31.core1.vie1.he.net 2001:470:0:4a8::1 | 11.3ms | 0% | AS6939 | HURRICANE - Hurricane Electric LLC, US |
| 7 | 2001:7f8:30:0:2:1:1:2401 @VIX / AAIX / SAIX / TIROL-IX / ERA-IX | 9.7ms | 0% | - | NA |
tracepath -6
1?: [LOCALHOST] 0.045ms pmtu 1500
1: 2a01:261:313:b814::1 1.776ms
1: no reply
2: 2a01:260:1::225 11.032ms
3: 2a01-260-1-1--9a.core6.t-2.net 2.654ms
4: 2a01-260-1-1--38.core6.t-2.net 2.917ms asymm 3
5: 100ge0-0-0-31.core1.vie1.he.net 10.881ms
6: 2001:7f8:30:0:2:1:1:2401 9.358ms asymm 5
7: 2001:7f8:30:0:2:1:1:2401 9.662ms asymm 5
8: 2001:4100:0:64::28 9.434ms reached
Resume: pmtu 1500 hops 8 back 6