IPv6 prefix announced, but nothing inside is responding yet. AS201102 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: 2a05:9540::1 · (no live host found) · address space: unknown · prefixes announced: 1
prefix(es): 2a05:9540::/29
MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO peering
MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO member - Open peering, peering member, since 2020-02-05. IPv6 LAN: 2001:7f8:b:100:1d1:a520:1102:148. Locations: -.
RPKI & ASPA
1 of 1 prefix(es) covered by a valid ROA.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a05:9540::/29 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS3302 /29 maxLen 29 (ripe); AS5602 /29 maxLen 29 (ripe); AS30722 /29 maxLen 29 (ripe); AS49524 /29 maxLen 29 (ripe) (+1 more) |
Random-IP probe (yarrp) into the AS' prefixes
We probed 15 arbitrary IPv6 address(es) inside AS201102's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:550:0:1000::9a36:4bda at hop 22 - that router answers ICMPv6 Echo. This is not in AS201102'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 2026-05-25T12:33:28Z
Failure detail — what to grep in your logs
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| go6lab | 2a00:8642:42::75 | 2a05:9540::1 | icmp6-echo | no_echo | 2026-05-25T12:33:28Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a05:9540::1 | icmp6-echo | no_echo | 2026-05-25T12:41:44Z |
| odin | 2607:fae0:a000::42 | 2a05:9540::1 | icmp6-echo | no_echo | 2026-05-25T12:33:09Z |
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 | 1.9ms | 0% | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 2 | gw.friends.steffann.nl 2a00:8642:1000:f000::1 | 2.2ms | 0%* | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 3 | 2a00:1ca8:1::194 | 2.1ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 4 | 2a03:3f40::10:41 | 3.2ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 5 | * | - | 40% | - | |
| 6 | * | - | - | - | |
| 7 | be2950.ccr42.fra05.atlas.cogentco.com 2001:550:0:1000::9a36:482a | 11.6ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | * | - | 90% | - | |
| 9 | port-channel5891.ccr91.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:3db5 | 25.7ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 10 | be4466.rcr51.b019138-1.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:4bbe | 25.4ms | 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 8 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.033ms pmtu 1500
1: 2a00:8642:42::3 1.958ms
1: 2a00:8642:42::3 1.546ms
2: gw.friends.steffann.nl 2.798ms
3: 2a00:1ca8:1::194 3.275ms
4: 2a03:3f40::10:41 2.935ms
5: no reply
6: be3457.ccr41.ams03.atlas.cogentco.com 4.978ms
7: be2950.ccr42.fra05.atlas.cogentco.com 11.588ms
8: no reply
9: port-channel5892.ccr92.mil02.atlas.cogentco.com 25.449ms
10: be4466.rcr51.b019138-1.mil02.atlas.cogentco.com 26.058ms
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 | 0.4ms | 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 | 10.1ms | - | 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 | 10.2ms | 0% | AS41327 | FIBERTELECOM-AS - Fiber Telecom S.p.A., IT |
| 6 | 2001:978:2:2a::e7:1 | 11.0ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 7 | be4918.agr62.mil02.atlas.cogentco.com 2001:550:0:1000::9a19:8c9 | 10.9ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | port-channel4689.ccr91.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:3e92 | 10.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 9 | be4466.rcr51.b019138-1.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:4bbe | 10.9ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 10 | * | - | - | - | |
| 11 | * | - | - | - | |
| 12 | * | - | - | - | |
| 13 | * | - | - | - | |
| 14 | * | - | - | - | |
| 15 | * | - | - | - | |
| 16 | * | - | - | - | |
| 17 | * | - | - | - | |
| 18 | * | - | - | - | |
| 19 | * | - | - | - | |
| 20 | * | - | - | - | |
| 21 | * | - | - | - | |
| 22 | * | - | - | - | |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
tracepath -6
1?: [LOCALHOST] 0.027ms pmtu 1500
1: karsolink-01.net.karsolink.com 0.827ms
1: karsolink-01.net.karsolink.com 0.594ms
2: 2a12:d8c0:109f:121::a1 0.681ms
3: 2a12:d8c0:101f:6::1 10.343ms
4: 2a03:b020:1:51::a 10.642ms
5: 2a03:b020::246 10.809ms asymm 6
6: 2001:978:2:2a::e7:1 11.184ms asymm 7
7: be4918.agr62.mil02.atlas.cogentco.com 11.468ms asymm 8
8: port-channel4689.ccr91.mil02.atlas.cogentco.com 10.788ms asymm 9
9: be5012.rcr51.b019138-1.mil02.atlas.cogentco.com 11.675ms asymm 10
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) 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 | * | - | 60% | - | |
| 4 | 2a00:ee0:1:15::2 | 1.0ms | 0% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 5 | 2001:41a8:20:2::169 | 8.7ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 6 | loa1-loop0-v6.loa.seabone.net 2001:41a8:4070::1 | 165.5ms | 0% | AS6762 | SEABONE-NET - TELECOM ITALIA SPARKLE S.p.A., IT |
| 7 | be3082.ccr41.lax04.atlas.cogentco.com 2001:550:3::1b5 | 178.9ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 8 | * | - | - | - | |
| 9 | be2932.ccr32.phx01.atlas.cogentco.com 2001:550:0:1000::9a36:2da1 | 182.8ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 10 | be5471.ccr21.elp02.atlas.cogentco.com 2001:550:0:1000::9a36:a639 | 173.1ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 11 | be3846.ccr32.dfw01.atlas.cogentco.com 2001:550:0:1000::9a36:a51d | 163.0ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 12 | be5383.ccr31.oma02.atlas.cogentco.com 2001:550:0:1000::9a36:7ea | 177.3ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 13 | be5214.ccr41.ord01.atlas.cogentco.com 2001:550:0:1000::9a36:a586 | 414.3ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 14 | port-channel2717.ccr91.cle04.atlas.cogentco.com 2001:550:0:1000::9a36:6de | 164.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 15 | be2994.ccr32.yyz02.atlas.cogentco.com 2001:550:0:1000::9a36:1fea | 169.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 16 | be3260.ccr22.ymq01.atlas.cogentco.com 2001:550:0:1000::9a36:2a5a | 181.8ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 17 | be3042.ccr21.lpl01.atlas.cogentco.com 2001:550:0:1000::9a36:2ca1 | 177.3ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 18 | port-channel8665.ccr91.lhr01.atlas.cogentco.com 2001:550:0:1000::9a36:4ada | 167.7ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 19 | be8670.ccr41.par01.atlas.cogentco.com 2001:550:0:1000::9a36:4b29 | 178.4ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 20 | * | - | 50% | - | |
| 21 | port-channel5889.ccr92.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:3c81 | 183.3ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 22 | be5012.rcr51.b019138-1.mil02.atlas.cogentco.com 2001:550:0:1000::9a36:4bda | 181.2ms | 0% | AS174 | COGENT-174 - Cogent Communications, LLC, US |
| 23 | * | - | - | - | |
| 24 | * | - | - | - |
Rate-limited ICMPv6: hop 3, hop 20 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.034ms pmtu 1500
1: fw1-lju.6connect.com 0.684ms
1: fw1-lju.6connect.com 1.471ms
2: no reply
3: 2a00:ee1:800:9::1 256.914ms
4: 2a00:ee0:1:10::2 1.122ms asymm 3
5: 2001:41a8:20:2::169 8.492ms asymm 6
6: loa1-loop0-v6.loa.seabone.net 203.965ms asymm 7
7: be3082.ccr41.lax04.atlas.cogentco.com 174.979ms
8: no reply
9: be2931.ccr31.phx01.atlas.cogentco.com 175.629ms asymm 8
10: be5471.ccr21.elp02.atlas.cogentco.com 173.197ms asymm 9
11: be3821.ccr31.dfw01.atlas.cogentco.com 165.811ms asymm 8
12: be5383.ccr31.oma02.atlas.cogentco.com 180.297ms asymm 8
13: be5214.ccr41.ord01.atlas.cogentco.com 170.599ms asymm 9
14: port-channel2717.ccr91.cle04.atlas.cogentco.com 162.343ms asymm 10
15: be2993.ccr31.yyz02.atlas.cogentco.com 176.355ms asymm 8
16: be3259.ccr21.ymq01.atlas.cogentco.com 179.709ms asymm 8
17: be3043.ccr22.lpl01.atlas.cogentco.com 181.792ms asymm 8
18: port-channel2133.ccr92.lhr01.atlas.cogentco.com 170.794ms asymm 10
19: be8670.ccr41.par01.atlas.cogentco.com 181.459ms asymm 9
20: no reply
21: port-channel5889.ccr92.mil02.atlas.cogentco.com 187.926ms asymm 8
22: be5012.rcr51.b019138-1.mil02.atlas.cogentco.com 185.295ms asymm 9
23: no reply
24: no reply
Too many hops: pmtu 1500
Resume: pmtu 1500