AS overview
Test target: 2a03:2b00::1 · (no live host found) · address space: mixed · prefixes announced: 2
prefix(es): 2a03:2b00::/33, 2a03:2b00::/32
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 2022-06-01. IPv6 LAN: 2001:7f8:b:100:1d1:a5d4:4831:47. Locations: -.
RPKI & ASPA
0 of 2 prefix(es) covered by a valid ROA, 2 not-found.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a03:2b00::/33 | - not-found | no covering VRP | |
2a03:2b00::/32 | - not-found | no covering VRP |
Random-IP probe (yarrp) into the AS' prefixes
We probed 30 arbitrary IPv6 address(es) inside AS44831's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:b01:2400:c9::1 at hop 24 - that router does not answer ICMPv6 Echo. This is not in AS44831'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 2026-05-25T12:32:05Z
Failure detail — what to grep in your logs
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| go6lab | 2a00:8642:42::75 | 2a03:2b00::1 | icmp6-echo | no_echo | 2026-05-25T12:32:05Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a03:2b00::1 | icmp6-echo | no_echo | 2026-05-25T12:40:24Z |
| odin | 2607:fae0:a000::42 | 2a03:2b00::1 | icmp6-echo | no_echo | 2026-05-25T12:31:50Z |
Attempt log (go6lab):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 13] Permission deniedtls→ 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 13] Permission deniedtls→ 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 13] Permission deniedtls→ 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 AS12874 (FASTWEB) · min PMTU on path: 1500
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a00:8642:42::3 | 1.3ms | 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 | 2.5ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 4 | 2a03:3f40::10:33 | 6.0ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 5 | 2001:7f8:1::a501:2874:1 | 101.1ms | 0% | - | NA |
| 6 | 2001:b00:1:1:3::13b | 29.5ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 7 | 2001:b00:1:1:1::1c5 | 22.3ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 8 | 2001:b01:2400:c9::2 | 28.3ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 9 | 2001:b01:2400:c9::1 | 28.6ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 10 | 2001:b01:2400:c9::1 | 28.7ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
tracepath -6
1?: [LOCALHOST] 0.045ms pmtu 1500
1: 2a00:8642:42::3 1.763ms
1: 2a00:8642:42::3 1.669ms
2: gw.friends.steffann.nl 1.855ms
3: 2a00:1ca8:1::194 3.501ms
4: 2a03:3f40::10:33 5.956ms
5: 2001:7f8:1::a501:2874:1 21.382ms
6: 2001:b00:1:1:3::139 21.434ms
7: 2001:b00:1:1:1::1c5 22.304ms
8: 2001:b01:2400:c9::2 29.124ms
9: 2001:b01:2400:c9::1 29.280ms
10: 2001:b01:2400:c9::1 28.269ms !A
Resume: pmtu 1500 From ITA host (Karsolink) transit only unreachable
filter likely at: past AS12874 (FASTWEB) · min PMTU on path: 1500
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 | 0.3ms | 0%* | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 3 | 2a12:d8c0:101f:6::1 | 10.0ms | 20% | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 4 | fastweb.minap.it 2001:7f8:c5::a501:2874:1 | 11.2ms | 90% | AS12874 | Fastweb S.p.A. |
| 5 | 2001:b00:1:1:1::1a7 | 9.7ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 6 | 2001:b00:1:1:1::1c3 | 10.2ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 7 | 2001:b01:2400:c9::2 | 17.3ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 8 | 2001:b01:2400:c9::1 | 17.1ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 9 | 2001:b01:2400:c9::1 | 17.0ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
Rate-limited ICMPv6: hop 3, hop 4 (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 0.617ms
1: karsolink-01.net.karsolink.com 0.789ms
2: no reply
3: 2a12:d8c0:101f:6::1 10.528ms
4: fastweb.minap.it 11.622ms
5: 2001:b00:1:1:1::1a7 10.155ms
6: 2001:b00:1:1:1::1c5 10.753ms
7: 2001:b01:2400:c9::2 17.715ms
8: 2001:b01:2400:c9::1 17.764ms
9: 2001:b01:2400:c9::1 17.563ms !A
Resume: pmtu 1500 From SLO host (6connect) transit only unreachable
filter likely at: past AS12874 (FASTWEB) · 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 | 2a03:a100:0:201:1::1 | 0.8ms | - | AS56635 | XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI |
| 4 | 2001:7f8:46:0:1::3303 | 7.8ms | 0% | AS51988 | ARNES-SIX - ARNES, SI |
| 5 | 2001:918:100:74::1 | 7.9ms | 0% | AS3303 | SWISSCOM - Swisscom (Schweiz) AG, CH |
| 6 | * | - | 80% | - | |
| 7 | 2001:b00:1:1:1::1ad | 10.0ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 8 | 2001:b00:1:1:1::1c3 | 11.0ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 9 | 2001:b01:2400:c9::2 | 17.8ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 10 | 2001:b01:2400:c9::1 | 17.8ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
| 11 | 2001:b01:2400:c9::1 | 17.6ms | 0% | AS12874 | FASTWEB - Fastweb SpA, IT |
Rate-limited ICMPv6: hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.033ms pmtu 1500
1: fw1-lju.6connect.com 0.501ms
1: fw1-lju.6connect.com 0.452ms
2: no reply
3: no reply
4: 2001:7f8:46:0:1::3303 7.946ms
5: 2001:918:100:74::1 8.240ms
6: 2001:4d98:a000::119 24.258ms asymm 11
7: 2001:b00:1:1:1::1ab 10.301ms asymm 9
8: 2001:b00:1:1:1::1c5 10.908ms asymm 10
9: 2001:b01:2400:c9::2 17.606ms asymm 11
10: 2001:b01:2400:c9::1 18.019ms asymm 12
11: 2001:b01:2400:c9::1 17.587ms !A
Resume: pmtu 1500