AS overview
Test target: 2a12:7bc0:104::1 · (no live host found) · address space: unknown · prefixes announced: 4
prefix(es): 2a12:7bc0:104::/48, 2a12:7bc0:103::/48, 2a12:7bc0:105::/48, 2a12:7bc0:102::/48
RPKI & ASPA
4 of 4 prefix(es) covered by a valid ROA.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a12:7bc0:104::/48 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS204903 /48 maxLen 48 (ripe); AS204903 /32 maxLen 32 (ripe) |
2a12:7bc0:103::/48 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS204903 /48 maxLen 48 (ripe); AS204903 /32 maxLen 32 (ripe) |
2a12:7bc0:105::/48 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS204903 /48 maxLen 48 (ripe); AS204903 /32 maxLen 32 (ripe) |
2a12:7bc0:102::/48 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS204903 /48 maxLen 48 (ripe); AS204903 /32 maxLen 32 (ripe) |
Random-IP probe (yarrp) into the AS' prefixes
We probed 30 arbitrary IPv6 address(es) inside AS204903's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a02:6ea0:c47e::1339 at hop 22 - that router answers ICMPv6 Echo. This is not in AS204903'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 active test inconclusive: no Echo Reply to 1300-byte probe.
method: ICMPv6 Echo + forged PTB, tested 2026-05-25T12:38:17Z
Failure detail — what to grep in your logs
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| go6lab | 2a00:8642:42::75 | 2a12:7bc0:104::1 | icmp6-echo | no_echo | 2026-05-25T12:38:17Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a12:7bc0:104::1 | icmp6-echo | no_echo | 2026-05-25T12:50:34Z |
| odin | 2607:fae0:a000::42 | 2a12:7bc0:104::1 | icmp6-echo | no_echo | 2026-05-25T12:37:47Z |
Attempt log (go6lab):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 113] No route to hosttls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (karsolink):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 113] No route to hosttls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (odin):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 113] No route to hosttls→ 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 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.
From NL host (go6lab) transit only unreachable
filter likely at: past AS60068 (CDN77) · 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 | gw.friends.steffann.nl 2a00:8642:1000:f000::1 | 1.8ms | 0%* | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 3 | speed-ix.cdn77.com 2001:7f8:b7::a506:68:1 | 3.1ms | 0% | - | NA |
| 4 | vl232.ams-eq6-core-2.cdn77.com 2a02:6ea0:1:3::34 | 2.9ms | 0% | - | NA |
| 5 | vl221.ams-eq6-dist-1.cdn77.com 2a02:6ea0:1:5::53 | 2.9ms | 0% | - | NA |
| 6 | unn-ams.cdn77.com 2a02:6ea0:c067::1338 | 3.8ms | 0% | AS60068 | CDN77 - Datacamp Limited, GB |
| 7 | unn-ams.cdn77.com 2a02:6ea0:c067::1338 | 1063.1ms | 90% | AS60068 | CDN77 - Datacamp Limited, GB |
Rate-limited ICMPv6: hop 7 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.040ms pmtu 1500
1: 2a00:8642:42::3 1.714ms
1: 2a00:8642:42::3 1.755ms
2: gw.friends.steffann.nl 2.291ms
3: speed-ix.cdn77.com 3.997ms
4: vl232.ams-eq6-core-2.cdn77.com 3.891ms
5: vl221.ams-eq6-dist-1.cdn77.com 4.058ms
6: unn-ams.cdn77.com 4.956ms
7: no reply
7: unn-ams.cdn77.com 3081.696ms !H
Resume: pmtu 1500 From ITA host (Karsolink) transit only unreachable
filter likely at: past AS201333 (NAQUADRIA-AS) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | * | - | 0%* | - | |
| 2 | * | - | 0%* | - | |
| 3 | 2a12:d8c0:101f:103::1 | 8.3ms | 0% | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 4 | 2001:7f8:b9::12:1 | 9.3ms | 0% | - | NA |
| 5 | 2a02:4720:0:8::215 | 9.4ms | 10% | AS201333 | NAQUADRIA-AS - Naquadria S.R.L., IT |
| 6 | * | - | 80% | - | |
| 7 | * | - | - | - | |
| 8 | * | - | - | - | |
| 9 | * | - | - | - | |
| 10 | * | - | - | - | |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 5, hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.036ms pmtu 1500
1: no reply
2: no reply
3: 2a12:d8c0:101f:103::1 8.955ms
4: 2001:7f8:b9::12:1 9.764ms asymm 5
5: 2a02:4720:0:8::215 10.029ms asymm 6
6: no reply
6: 2a02:4720:0:8::215 3124.880ms !H
Resume: pmtu 1500 From SLO host (6connect) transit only unreachable
filter likely at: past AS20473 (AS-VULTR) · 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 | 1.2ms | 0%* | AS8038 | 6CONNECT - 6connect, Inc., US |
| 2 | * | - | 0%* | - | |
| 3 | * | - | 40% | - | |
| 4 | 2a00:ee0:1:15::2 | 1.1ms | 0% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 5 | decix.fkt.vultr.com 2001:7f8::4ff9:0:1 | 20.5ms | 0% | - | NA |
| 6 | ethernetae9-sr1.fkt3.constant.com 2001:19f0:fc00::a4b:22a | 21.0ms | 0% | - | NA |
| 7 | ethernetet-0-0-50-ds1-j3-e01-b.fkt3.constant.com 2001:19f0:fc00::a4b:5e | 17.6ms | 0% | - | NA |
| 8 | 2001:19f0:6c00:250::33 | 14.4ms | 0% | AS20473 | AS-VULTR - The Constant Company, LLC, US |
| 9 | 2001:19f0:6c01:7a5:5400:3ff:fe09:c5c4 | 14.6ms | 0% | AS20473 | AS-VULTR - The Constant Company, LLC, US |
| 10 | 2001:19f0:6c01:7a5:5400:3ff:fe09:c5c4 | 1103.0ms | 70% | AS20473 | AS-VULTR - The Constant Company, LLC, US |
Rate-limited ICMPv6: hop 3, hop 10 (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 0.401ms
1: fw1-lju.6connect.com 0.600ms
2: ccr-to-fw-ccr1-gw-lju.6connect.com 0.668ms
3: 2a00:ee1:800:9::1 1.792ms
4: 2a00:ee0:1:15::2 1.104ms asymm 3
5: decix.fkt.vultr.com 20.549ms asymm 15
6: ethernetae2-sr2.fkt3.constant.com 19.202ms asymm 11
7: ethernetet-0-0-53-ds1-j3-e01-b.fkt3.constant.com 15.285ms asymm 12
8: 2001:19f0:6c00:250::33 15.588ms asymm 12
9: 2001:19f0:6c01:7a5:5400:3ff:fe09:c5c4 14.952ms asymm 14
10: no reply
10: 2001:19f0:6c01:7a5:5400:3ff:fe09:c5c4 3121.444ms !H
Resume: pmtu 1500