AS overview
Test target: 2a01:9ce0:0:1:7ec2:55ff:fe25:2c00 · via IPv6 Hitlist (responsive) · address space: mixed · prefixes announced: 1
prefix(es): 2a01:9ce0::/32
Targets & per-vantage-point probe results (8 target(s) across 3 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 | NL host (go6lab) | ITA host (Karsolink) | SLO host (6connect) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ping | 1500B | :80 | :443 | reached | ||
2a01:9ce0:0:1:7ec2:55ff:fe25:2c00 | hit | ✗ | ✗ | open | ? | - | ✓ | ✓ | open | refused | - | ✓ | ✓ | open | refused | - |
2a01:9ce0:0:1:7ec2:55ff:fe4e:b2e8 | hit | ✗ | ✗ | open | open | - | ✓ | ✓ | open | open | - | ✓ | ✓ | open | open | - |
2a01:9ce0:0:1:8077:4bff:fec4:cf6e | hit | ✗ | ✗ | ? | ? | ✓ | ✗ | ✗ | ? | ? | ✓ | ✓ | ✓ | ? | ? | - |
2a01:9ce0:0:1::1 | hit | ✗ | ✗ | ? | ? | - | ✓ | ✓ | refused | refused | - | ✓ | ✓ | refused | refused | - |
2a01:9ce0:0:1::2 | hit | ✗ | ✗ | ? | ? | - | ✓ | ✓ | refused | refused | - | ✓ | ✓ | refused | refused | - |
2a01:9ce0:0:1::3 | hit | ✗ | ✗ | ? | ? | ✓ | ✓ | ✓ | refused | refused | - | ✓ | ✓ | refused | refused | ✓ |
2a01:9ce0:0:1::4 | hit | ✗ | ✗ | ? | ? | - | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | ✓ |
2a01:9ce0:0:1::5 | hit | ✗ | ✗ | ? | ? | ✓ | ✓ | ✓ | refused | refused | ✓ | ✓ | ✓ | refused | refused | - |
SIX peering
SIX member - open peering, peering member, since 2018-10-09. IPv6 LAN: 2001:7f8:46:0:1:0:2:8682. Locations: lj_tpl.
- rs1-lan1-ipv6 →
2001:7f8:46:0:1:0:2:8682Established (loc: lj_tpl, since 2026-02-25) - rs2-lan1-ipv6 →
2001:7f8:46:0:1:0:2:8682Established (loc: lj_tpl, since 2026-05-12)
Announces via SIX route servers: 3 prefix(es) - 2a00:a360::/32, 2a00:a362::/32, 2a01:9ce0::/32
RPKI & ASPA
1 of 1 prefix(es) covered by a valid ROA.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a01:9ce0::/32 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS28682 /32 maxLen 32 (ripe) |
Random-IP probe (yarrp) into the AS' prefixes
We probed 15 arbitrary IPv6 address(es) inside AS28682's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a02:800:1:2001::3 at hop 24 - that router answers ICMPv6 Echo. This is not in AS28682's announced prefix; operationally it's the AS-edge / peering interface (often on a SIX 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:
- NL host (go6lab): inconclusive: no Echo Reply to 1300-byte probe. (ICMPv6 Echo + forged PTB)
- ITA host (Karsolink): inconclusive: no Echo Reply to 1300-byte probe. (ICMPv6 Echo + forged PTB)
- SLO host (6connect): Type 2 honored. Forged PTB accepted; next response shrunk. (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) |
|---|---|---|---|---|---|
| go6lab | 2a00:8642:42::75 | 2a01:9ce0:0:1:7ec2:55ff:fe25:2c00 | icmp6-echo | no_echo | 2026-05-30T10:33:30Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a01:9ce0:0:1:7ec2:55ff:fe25:2c00 | icmp6-echo | no_echo | 2026-05-30T10:40:02Z |
| odin | 2607:fae0:a000::42 | 2a01:9ce0:0:1:7ec2:55ff:fe25:2c00 | icmp6-echo | honored | 2026-05-30T10:33:20Z |
Attempt log (go6lab):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: timed outtls→ no_tcp: TLS connect failedhttp→ inconclusive (size_before=848, size_after=None): natural max segment 848B already <= 1220B; nothing to shrink
Attempt log (karsolink):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: timed outtls→ no_tcp: TLS connect failedhttp→ inconclusive (size_before=848, size_after=None): natural max segment 848B already <= 1220B; nothing to shrink
Attempt log (odin):
icmp6-echo→ honored (size_before=1460, size_after=None)dns-tcp→ no_tcp: connect failed: timed outtls→ no_tcp: TLS connect failedhttp→ inconclusive (size_before=848, size_after=None): natural max segment 848B already <= 1220B; nothing to shrink
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 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 one of our two source IPs, the drop is path-asymmetric — one transit on the asymmetric route is filtering, the other is not.
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 2a01:9ce0:0:1:7ec2:55ff:fe4e:b2e8
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 | 2a00:1ca8:1::194 | |
| 4 | 2a03:3f40::10:33 | |
| 5 | 2001:7f8:13::a500:3212:1 | |
| 6 | 2a00:fc0:4320:c::a | |
| 7 | 2a00:fc0:4320:c::b | |
| 8 | <span class='muted'>no reply</span> | |
| 9 | <span class='muted'>no reply</span> | |
| 10 | <span class='muted'>no reply</span> | |
| 11 | <span class='muted'>no reply</span> | |
| 12 | <span class='muted'>no reply</span> | |
| 13 | <span class='muted'>no reply</span> | |
| 14 | <span class='muted'>no reply</span> | |
| 15 | <span class='muted'>no reply</span> | |
| 16 | <span class='muted'>no reply</span> | |
| 17 | <span class='muted'>no reply</span> | |
| 18 | <span class='muted'>no reply</span> | |
| 19 | <span class='muted'>no reply</span> | |
| 20 | <span class='muted'>no reply</span> | |
| 21 | <span class='muted'>no reply</span> | |
| 22 | <span class='muted'>no reply</span> | |
| 23 | <span class='muted'>no reply</span> | |
| 24 | <span class='muted'>no reply</span> |
karsolink — verdict not_honored
verdict = not_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 | <span class='muted'>no reply</span> | |
| 6 | <span class='muted'>no reply</span> | |
| 7 | 2001:7f8::239f:0:1 | |
| 8 | 2a02:800:1:6000::1 | |
| 9 | 2a02:800:1:2001::3 | |
| 10 | <span class='muted'>no reply</span> | |
| 11 | <span class='muted'>no reply</span> | |
| 12 | <span class='muted'>no reply</span> | |
| 13 | <span class='muted'>no reply</span> | |
| 14 | <span class='muted'>no reply</span> | |
| 15 | <span class='muted'>no reply</span> | |
| 16 | <span class='muted'>no reply</span> | |
| 17 | <span class='muted'>no reply</span> | |
| 18 | <span class='muted'>no reply</span> | |
| 19 | <span class='muted'>no reply</span> | |
| 20 | <span class='muted'>no reply</span> | |
| 21 | <span class='muted'>no reply</span> | |
| 22 | <span class='muted'>no reply</span> | |
| 23 | <span class='muted'>no reply</span> | |
| 24 | <span class='muted'>no reply</span> |
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 | 2001:7f8:46:0:1:0:2:8682 | |
| 5 | <span class='muted'>no reply</span> | |
| 6 | <span class='muted'>no reply</span> | |
| 7 | <span class='muted'>no reply</span> | |
| 8 | <span class='muted'>no reply</span> | |
| 9 | <span class='muted'>no reply</span> | |
| 10 | <span class='muted'>no reply</span> | |
| 11 | <span class='muted'>no reply</span> | |
| 12 | <span class='muted'>no reply</span> | |
| 13 | <span class='muted'>no reply</span> | |
| 14 | <span class='muted'>no reply</span> | |
| 15 | <span class='muted'>no reply</span> | |
| 16 | <span class='muted'>no reply</span> | |
| 17 | <span class='muted'>no reply</span> | |
| 18 | <span class='muted'>no reply</span> | |
| 19 | <span class='muted'>no reply</span> | |
| 20 | <span class='muted'>no reply</span> | |
| 21 | <span class='muted'>no reply</span> | |
| 22 | <span class='muted'>no reply</span> | |
| 23 | <span class='muted'>no reply</span> | |
| 24 | <span class='muted'>no reply</span> |
From NL host (go6lab) icmp blocked
filter likely at: past AS3212 (TELEMACH) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a00:8642:42::3 | 1.2ms | 0% | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 2 | * | - | 0%* | - | |
| 3 | 2a00:1ca8:1::194 | 2.4ms | 20% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 4 | 2a03:3f40::10:33 | 4.4ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 5 | 2001:7f8:13::a500:3212:1 | 31.1ms | 0% | - | NA |
| 6 | 2a00:fc0:4320:c::a | 29.7ms | 0% | AS3212 | TELEMACH - Telemach Slovenija d.o.o., SI |
| 7 | 2a00:fc0:4320:c::b | 27.4ms | 90% | AS3212 | TELEMACH - Telemach Slovenija d.o.o., SI |
| 8 | * | - | - | - | |
| 9 | * | - | - | - | |
| 10 | * | - | - | - | |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 3, hop 7 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.029ms pmtu 1500
1: 2a00:8642:42::3 1.681ms
1: 2a00:8642:42::3 1.521ms
2: no reply
3: no reply
4: 2a03:3f40::10:33 7.373ms
5: 2001:7f8:13::a500:3212:1 31.614ms asymm 10
6: 2a00:fc0:4320:c::a 29.869ms asymm 10
7: 2a00:fc0:4320:c::b 29.230ms asymm 11
8: no reply
9: no reply
10: no reply
11: no reply
12: no reply
13: no reply
14: no reply
15: no reply
16: no reply
17: no reply
18: no reply
19: no reply
20: no reply
21: no reply
22: no reply
23: no reply
24: no reply
Too many hops: pmtu 1500
Resume: pmtu 1500 From ITA host (Karsolink) open
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 | * | - | 60% | - | |
| 4 | * | - | - | - | |
| 5 | * | - | - | - | |
| 6 | * | - | - | - | |
| 7 | decix.softnet.si 2001:7f8::239f:0:1 | 20.9ms | - | - | NA |
| 8 | sn-lju-hu-0-1-0-0-81-slo.ntwk.softnet.si 2a02:800:1:6000::1 | 26.5ms | - | AS9119 | SOFTNET-AS - SOFTNET d.o.o., SI |
| 9 | 2a02:800:1:2001::3 | 27.8ms | 0% | AS9119 | SOFTNET-AS - SOFTNET d.o.o., SI |
| 10 | * | - | 0% | - | |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.043ms pmtu 1500
1: karsolink-01.net.karsolink.com 0.889ms
2: 2a12:d8c0:109f:121::a1 0.853ms
3: 2a12:d8c0:101f:6::1 10.259ms
4: no reply
5: no reply
6: no reply
7: decix.softnet.si 22.306ms
8: sn-lju-hu-0-1-0-0-81-slo.ntwk.softnet.si 27.162ms
9: 2a02:800:1:2001::3 28.285ms
10: no reply
11: no reply
12: no reply
13: no reply
14: no reply
15: no reply
16: no reply
17: no reply
18: no reply
19: no reply
20: no reply
21: no reply
22: no reply
23: no reply
24: no reply
Too many hops: pmtu 1500
Resume: pmtu 1500 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 | 0.3ms | 0%* | AS8038 | 6CONNECT - 6connect, Inc., US |
| 2 | * | - | - | - | |
| 3 | * | - | 70% | - | |
| 4 | 2001:7f8:46:0:1:0:2:8682 @SIX | 3.0ms | 0% | AS51988 | ARNES-SIX - ARNES, SI |
| 5 | * | - | 0% | - | |
| 6 | * | - | - | - | |
| 7 | * | - | - | - | |
| 8 | * | - | - | - | |
| 9 | * | - | - | - | |
| 10 | * | - | - | - | |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.026ms pmtu 1500
1: fw1-lju.6connect.com 0.678ms
1: fw1-lju.6connect.com 0.452ms
2: ccr-to-fw-ccr1-gw-lju.6connect.com 1.629ms
3: 2a03:a100:0:201:1::1 0.990ms
4: 2001:7f8:46:0:1:0:2:8682 1.486ms
5: no reply
6: no reply
7: no reply
8: no reply
9: no reply
10: no reply
11: no reply
12: no reply
13: no reply
14: no reply
15: no reply
16: no reply
17: no reply
18: no reply
19: no reply
20: no reply
21: no reply
22: no reply
23: no reply
24: no reply
Too many hops: pmtu 1500
Resume: pmtu 1500