IPv6 prefix announced, but nothing inside is responding yet. AS207590 announces 1 IPv6 prefix(es) to the global routing table - that’s the part that BGP and our route-server scrape confirm. But our active discovery (curated hostnames, holder-derived domains, authoritative DNS NS/SOA/MX, certificate-transparency hostnames, RIPE Atlas, RDAP, IPv6 Hitlist) found no ICMPv6-responsive host inside the prefix on either vantage, and a yarrp pass against random addresses inside the prefix produced zero in-prefix hops (no router on the path through the AS replied with Time-Exceeded for any random target). That combination usually means the announcement is configured but the addresses inside aren’t in active use yet. The BGP route is there; the operational deployment is still ahead.
AS overview
Test target: 2a0f:f3c0::1 · (no live host found) · address space: mixed · prefixes announced: 1
prefix(es): 2a0f:f3c0::/48
RPKI & ASPA
1 of 1 prefix(es) covered by a valid ROA.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a0f:f3c0::/48 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS207590 /48 maxLen 48 (ripe); AS207590 /29 maxLen 29 (ripe) |
Random-IP probe (yarrp) into the AS' prefixes
We probed 15 arbitrary IPv6 address(es) inside AS207590's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:550:0:1000::9a19:1c1 at hop 22 - that router answers ICMPv6 Echo. This is not in AS207590'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 2026-05-25T12:37:38Z
Failure detail — what to grep in your logs
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| go6lab | 2a00:8642:42::75 | 2a0f:f3c0::1 | icmp6-echo | no_echo | 2026-05-25T12:37:38Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a0f:f3c0::1 | icmp6-echo | no_echo | 2026-05-25T12:48:49Z |
| odin | 2607:fae0:a000::42 | 2a0f:f3c0::1 | icmp6-echo | no_echo | 2026-05-25T12:37:08Z |
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→ 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: timed outtls→ 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: timed outtls→ 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 AS174 (COGENT-174) · min PMTU on path: 1500
0/4
Echo small (56B) -
0/4
Echo 1500B (DF) -
no
Type 1 dest-unreach
-
TCP responds on
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a00:8642:42::3 | 1.5ms | 0% | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 2 | * | - | 0%* | - | |
| 3 | 2a00:1ca8:1::194 | 2.9ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 4 | 2a03:3f40::10:41 | 3.0ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 5 | * | - | 70% | - | |
| 6 | * | - | 60% | - | |
| 7 | be2950.ccr42.fra05.atlas.cogentco.com 2001:550:0:1000::9a36:482a | 10.9ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | * | - | 80% | - | |
| 9 | be6038.rcr71.nue01.atlas.cogentco.com 2001:550:0:1000::9a36:485e | 17.5ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 10 | be6039.nr71.b040138-0.nue01.atlas.cogentco.com 2001:550:0:1000::9a19:1c1 | 19.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 5, hop 6, hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.034ms pmtu 1500
1: 2a00:8642:42::3 1.774ms
1: 2a00:8642:42::3 1.378ms
2: gw.friends.steffann.nl 2.535ms
3: 2a00:1ca8:1::194 2.867ms
4: 2a03:3f40::10:41 4.325ms
5: no reply
6: no reply
7: be2950.ccr42.fra05.atlas.cogentco.com 12.134ms
8: no reply
9: be6037.rcr71.nue01.atlas.cogentco.com 19.434ms
10: be6039.nr71.b040138-0.nue01.atlas.cogentco.com 19.795ms
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) transit only unreachable
filter likely at: past AS174 (COGENT-174) · min PMTU on path: 1500
0/4
Echo small (56B) -
0/4
Echo 1500B (DF) -
no
Type 1 dest-unreach
-
TCP responds on
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | karsolink-01.net.karsolink.com 2a12:d8c0:105a:9001::1 | 0.3ms | 0%* | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 2 | 2a12:d8c0:109f:121::a1 | 0.4ms | 0%* | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 3 | 2a12:d8c0:101f:6::1 | 10.0ms | 0% | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 4 | 2a03:b020:1:51::a | 10.3ms | 0% | AS41327 | FIBERTELECOM-AS - Fiber Telecom S.p.A., IT |
| 5 | 2a03:b020::246 | 10.3ms | 0% | AS41327 | FIBERTELECOM-AS - Fiber Telecom S.p.A., IT |
| 6 | 2001:978:2:2a::e7:1 | 11.2ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 7 | be4823.agr61.mil02.atlas.cogentco.com 2001:550:0:1000::9a19:8c5 | 10.7ms | 10% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | port-channel4690.ccr92.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:3f3e | 10.3ms | 10% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 9 | * | - | - | - | |
| 10 | be6038.rcr71.nue01.atlas.cogentco.com 2001:550:0:1000::9a36:485e | 21.5ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 11 | be6039.nr71.b040138-0.nue01.atlas.cogentco.com 2001:550:0:1000::9a19:1c1 | 21.6ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 7, hop 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.032ms pmtu 1500
1: karsolink-01.net.karsolink.com 0.852ms
2: 2a12:d8c0:109f:121::a1 0.966ms
3: 2a12:d8c0:101f:6::1 10.895ms
4: 2a03:b020:1:51::a 11.045ms
5: 2a03:b020::246 10.791ms asymm 6
6: 2001:978:2:2a::e7:1 11.451ms asymm 7
7: be4918.agr62.mil02.atlas.cogentco.com 11.369ms asymm 8
8: port-channel3333.ccr91.mil02.atlas.cogentco.com 10.833ms asymm 9
9: no reply
10: be6037.rcr71.nue01.atlas.cogentco.com 21.784ms asymm 11
11: be6039.nr71.b040138-0.nue01.atlas.cogentco.com 22.276ms asymm 12
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) transit only unreachable
filter likely at: past AS174 (COGENT-174) · min PMTU on path: 1500
0/4
Echo small (56B) -
0/4
Echo 1500B (DF) -
no
Type 1 dest-unreach
-
TCP responds on
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 | 2a00:ee1:800:9::1 | 2.2ms | 0% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 4 | 2a00:ee0:1:15::2 | 1.1ms | 0% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 5 | 2001:41a8:20:2::169 | 8.8ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 6 | loa1-loop0-v6.loa.seabone.net 2001:41a8:4070::1 | 183.8ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 7 | be3082.ccr41.lax04.atlas.cogentco.com 2001:550:3::1b5 | 181.0ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | * | - | - | - | |
| 9 | be2932.ccr32.phx01.atlas.cogentco.com 2001:550:0:1000::9a36:2da1 | 182.6ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 10 | be5471.ccr21.elp02.atlas.cogentco.com 2001:550:0:1000::9a36:a639 | 173.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 11 | be3846.ccr32.dfw01.atlas.cogentco.com 2001:550:0:1000::9a36:a51d | 168.1ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 12 | be5384.ccr32.oma02.atlas.cogentco.com 2001:550:0:1000::9a36:1f5e | 175.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 13 | be5214.ccr41.ord01.atlas.cogentco.com 2001:550:0:1000::9a36:a586 | 170.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 14 | port-channel2718.ccr92.cle04.atlas.cogentco.com 2001:550:0:1000::9a36:782 | 170.6ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 15 | be8022.ccr21.alb02.atlas.cogentco.com 2001:550:0:1000::9a36:a9ba | 172.0ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 16 | be8029.ccr31.bos01.atlas.cogentco.com 2001:550:0:1000::9a36:a9dd | 169.0ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 17 | port-channel3467.ccr92.lhr01.atlas.cogentco.com 2001:550:0:1000::9a36:5e2e | 164.1ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 18 | * | - | 60% | - | |
| 19 | be7946.ccr42.fra05.atlas.cogentco.com 2001:550:0:1000::9a36:4876 | 186.2ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 20 | * | - | 90% | - | |
| 21 | be6037.rcr71.nue01.atlas.cogentco.com 2001:550:0:1000::9a36:485a | 177.5ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 22 | be6039.nr71.b040138-0.nue01.atlas.cogentco.com 2001:550:0:1000::9a19:1c1 | 179.3ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 18, hop 20 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.035ms pmtu 1500
1: fw1-lju.6connect.com 0.541ms
1: fw1-lju.6connect.com 0.464ms
2: no reply
3: 2a00:ee1:800:9::1 2.398ms
4: 2a00:ee0:1:10::2 1.202ms asymm 3
5: 2001:41a8:20:2::169 9.139ms asymm 6
6: loa1-loop0-v6.loa.seabone.net 165.343ms asymm 7
7: be3082.ccr41.lax04.atlas.cogentco.com 184.562ms
8: no reply
9: be2931.ccr31.phx01.atlas.cogentco.com 171.211ms asymm 8
10: be5471.ccr21.elp02.atlas.cogentco.com 175.325ms asymm 9
11: be3846.ccr32.dfw01.atlas.cogentco.com 159.875ms asymm 7
12: be5384.ccr32.oma02.atlas.cogentco.com 175.632ms asymm 9
13: be5214.ccr41.ord01.atlas.cogentco.com 167.326ms asymm 9
14: port-channel2717.ccr91.cle04.atlas.cogentco.com 164.822ms asymm 10
15: be8023.ccr22.alb02.atlas.cogentco.com 176.036ms asymm 8
16: be8029.ccr31.bos01.atlas.cogentco.com 177.003ms asymm 8
17: port-channel8668.ccr91.lhr01.atlas.cogentco.com 171.244ms asymm 9
18: no reply
19: be7946.ccr42.fra05.atlas.cogentco.com 185.364ms asymm 7
20: no reply
21: be6037.rcr71.nue01.atlas.cogentco.com 182.705ms asymm 9
22: be6039.nr71.b040138-0.nue01.atlas.cogentco.com 182.168ms asymm 10
23: no reply
24: no reply
Too many hops: pmtu 1500
Resume: pmtu 1500