AS202523 NEHOS-ASN Nehos S.R.L.

IPv6 prefix announced, but nothing inside is responding yet. AS202523 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:ee80::1 · (no live host found) · address space: PA · prefixes announced: 1

prefix(es): 2a05:ee80::/29

MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO peering

Not an MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO member, but our traceroute path crosses the MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO LAN from SLO host (6connect) - reached via an MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO-resident transit operator.

RPKI & ASPA

1 of 1 prefix(es) covered by a valid ROA.

Prefix	RPKI state	Reason	Covering VRP(s)
`2a05:ee80::/29`	✓ valid	matched VRP (correct origin, length within maxLength)	AS202523 /29 maxLen 29 (ripe)

Random-IP probe (yarrp) into the AS' prefixes

We probed 15 arbitrary IPv6 address(es) inside AS202523's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a05:eb87:1:103::3 at hop 10 - that router answers ICMPv6 Echo. This is not in AS202523'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 2026-05-25T12:33:40Z

Failure detail — what to grep in your logs

vantage	our source	your target	method	result	tested (UTC)
go6lab	`2a00:8642:42::75`	`2a05:ee80::1`	`icmp6-echo`	no_echo	2026-05-25T12:33:40Z
karsolink	`2a12:d8c0:105a:9001::a154`	`2a05:ee80::1`	`icmp6-echo`	no_echo	2026-05-25T12:41:55Z
odin	`2607:fae0:a000::42`	`2a05:ee80::1`	`icmp6-echo`	no_echo	2026-05-25T12:33:19Z

Attempt log (go6lab):

icmp6-echo → no_echo: no Echo Reply to 1300-byte probe
dns-tcp → no_tcp: connect failed: timed out
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (karsolink):

icmp6-echo → no_echo: no Echo Reply to 1300-byte probe
dns-tcp → no_tcp: connect failed: timed out
tls → no_tcp: TLS connect failed
http → no_tcp: tcp/80 not open

Attempt log (odin):

icmp6-echo → no_echo: no Echo Reply to 1300-byte probe
dns-tcp → no_tcp: connect failed: timed out
tls → no_tcp: TLS connect failed
http → 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 AS39479 (NS3-ASN) · min PMTU on path: 1500

0/4

Echo small (56B) -

0/4

Echo 1500B (DF) -

Type 1 dest-unreach

TCP responds on

Path (traceroute + mtr + PTR)

#	IP / PTR	RTT	mtr loss	AS	AS holder
1	2a00:8642:42::3	1.4ms	0%	AS203993	STEFFANN-DC-AS - S.J.M. Steffann, NL
2	gw.friends.steffann.nl 2a00:8642:1000:f000::1	1.5ms	0%*	AS203993	STEFFANN-DC-AS - S.J.M. Steffann, NL
3	2a00:1ca8:1::194	2.2ms	10%	AS50673	Serverius-as - Serverius Holding B.V., NL
4	2a03:3f40::10:41	2.4ms	0%	AS50673	Serverius-as - Serverius Holding B.V., NL
5	speed-ix.fibertelecom.it 2001:7f8:b7::a504:1327:1	4.2ms	0%	-	NA
6	2a03:b020::227	23.9ms	0%	AS41327	FIBERTELECOM-AS - Fiber Telecom S.p.A., IT
7	2a03:b020:1:1f::b	24.7ms	0%	AS41327	FIBERTELECOM-AS - Fiber Telecom S.p.A., IT
8	rt-as50877.as214443.net 2a01:e600:1::b	24.8ms	0%	AS214443	BEBYTE - BE BYTE SRL, IT
9	2a0a:f980:1:101::2	25.0ms	0%	AS50877	AIRBEAM-AS - Airbeam S.r.l., IT
10	2a05:eb87:1:103::3	24.1ms	0%	AS39479	NS3-ASN - NS3 s.r.l., IT
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]                        0.038ms pmtu 1500
 1:  2a00:8642:42::3                                       1.669ms 
 1:  2a00:8642:42::3                                       1.766ms 
 2:  gw.friends.steffann.nl                                2.705ms 
 3:  2a00:1ca8:1::194                                      3.021ms 
 4:  2a03:3f40::10:41                                      3.234ms 
 5:  speed-ix.fibertelecom.it                              4.745ms asymm  3 
 6:  2a03:b020::227                                       26.099ms asymm  4 
 7:  2a03:b020:1:1f::b                                    25.672ms asymm 13 
 8:  rt-as50877.as214443.net                              32.239ms asymm 14 
 9:  2a0a:f980:1:101::2                                   26.255ms asymm 15 
10:  2a05:eb87:1:103::3                                   25.125ms asymm 16 
11:  no reply
12:  no reply
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14:  no reply
15:  no reply
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18:  no reply
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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 AS39479 (NS3-ASN) · min PMTU on path: 1500

0/4

Echo small (56B) -

0/4

Echo 1500B (DF) -

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:d8c0:109f:106::a2	3.1ms	0%	AS204471	KARSOLINK - 2S Computers SRL, IT
4	2a12:d8c0:1a1::a2	20.9ms	0%	AS204471	KARSOLINK - 2S Computers SRL, IT
5	2a0a:f980:1:101::2	3.6ms	0%	AS50877	AIRBEAM-AS - Airbeam S.r.l., IT
6	2a05:eb87:1:103::3	3.4ms	0%	AS39479	NS3-ASN - NS3 s.r.l., IT
7	*	-	-	-
8	*	-	-	-
9	*	-	-	-
10	*	-	-	-
11	*	-	-	-
12	*	-	-	-
13	*	-	-	-
14	*	-	-	-
15	*	-	-	-
16	*	-	-	-
17	*	-	-	-
18	*	-	-	-
19	*	-	-	-
20	*	-	-	-
21	*	-	-	-
22	*	-	-	-
23	*	-	-	-
24	*	-	-	-

tracepath -6

 1?: [LOCALHOST]                        0.109ms pmtu 1500
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                                0.993ms 
 3:  2a12:d8c0:109f:106::a2                                3.607ms 
 4:  2a12:d8c0:1a1::a2                                     3.784ms 
 5:  2a0a:f980:1:101::2                                    4.110ms 
 6:  2a05:eb87:1:103::3                                    3.925ms asymm  5 
 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
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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 AS39479 (NS3-ASN) · min PMTU on path: 1500

0/4

Echo small (56B) -

0/4

Echo 1500B (DF) -

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	*	-	0%	-
4	2a00:ee0:1:15::2	1.0ms	0%	AS5603	SIOL-NET - Telekom Slovenije, d.d., SI
5	2a11:4142:2002	1.1ms	0%	-
6	2620:107:4008:e85::2	8.1ms	0%	-	NA
7	ns3-AS39479-v6.mix-it.net @MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO 2001:7f8:b:100:1d1:a5d3:9479:169	13.3ms	0%	-	NA
8	2a05:eb87:1:105::3	13.4ms	0%	AS39479	NS3-ASN - NS3 s.r.l., IT
9	*	-	-	-
10	*	-	-	-
11	*	-	-	-
12	*	-	-	-
13	*	-	-	-
14	*	-	-	-
15	*	-	-	-
16	*	-	-	-
17	*	-	-	-
18	*	-	-	-
19	*	-	-	-
20	*	-	-	-
21	*	-	-	-
22	*	-	-	-
23	*	-	-	-
24	*	-	-	-

tracepath -6

 1?: [LOCALHOST]                        0.030ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.415ms 
 1:  fw1-lju.6connect.com                                  8.970ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     3.245ms 
 4:  2a00:ee0:1:15::2                                      3.423ms asymm  3 
 5:  2a11:4142:2002::                                      2.135ms asymm  6 
 6:  2620:107:4008:e85::2                                  8.703ms asymm  7 
 7:  ns3-AS39479-v6.mix-it.net                            13.772ms asymm  8 
 8:  2a05:eb87:1:105::3                                   13.606ms asymm  9 
 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
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20:  no reply
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23:  no reply
24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500