AS210278 - SKYIT-BB Sky Italia srlPARPKI ✓ 1/1ASPA -

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IPv6 prefix announced, but nothing inside is responding yet. AS210278 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: 2a0e:400::1 · (no live host found) · address space: PA · prefixes announced: 1

prefix(es): 2a0e:400::/25

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 2020-05-15. IPv6 LAN: 2001:7f8:b:100:1d1:a521:278:163. Locations: -.

RPKI & ASPA

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

PrefixRPKI stateReasonCovering VRP(s)
2a0e:400::/25✓ validmatched VRP (correct origin, length within maxLength)AS210278 /25 maxLen 25 (ripe)

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

We probed 15 arbitrary IPv6 address(es) inside AS210278's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:2034:a:2f4:: at hop 8 - that router answers ICMPv6 Echo. This is not in AS210278'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 2026-05-25T12:36:49Z

Failure detail — what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
go6lab2a00:8642:42::752a0e:400::1icmp6-echono_echo2026-05-25T12:36:49Z
karsolink2a12:d8c0:105a:9001::a1542a0e:400::1icmp6-echono_echo2026-05-25T12:47:58Z
odin2607:fae0:a000::422a0e:400::1icmp6-echono_echo2026-05-25T12:36:22Z

Attempt log (go6lab):

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

Attempt log (karsolink):

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

Attempt log (odin):

  1. icmp6-echo → no_echo: no Echo Reply to 1300-byte probe
  2. dns-tcp → no_tcp: connect failed: timed out
  3. tls → no_tcp: TLS connect failed
  4. 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: no path · 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 / PTRRTTmtr lossASAS holder
12a00:8642:42::30.9ms0%AS203993STEFFANN-DC-AS - S.J.M. Steffann, NL
2gw.friends.steffann.nl
2a00:8642:1000:f000::1		2.1ms0%*AS203993STEFFANN-DC-AS - S.J.M. Steffann, NL
32a00:1ca8:1::1942.1ms40%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:412.2ms0%AS50673Serverius-as - Serverius Holding B.V., NL
52001:978:2:40::3:13.7ms40%AS174COGENT-174 - Cogent Communications, LLC, US
6*-90%-
72001:978:3::264.2ms0%AS174COGENT-174 - Cogent Communications, LLC, US
82001:2034:a:693.6ms0%-
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Rate-limited ICMPv6: hop 3, hop 5, hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.027ms pmtu 1500
 1:  2a00:8642:42::3                                       2.098ms 
 1:  2a00:8642:42::3                                       1.928ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      2.533ms 
 4:  2a03:3f40::10:41                                      2.540ms 
 5:  no reply
 6:  no reply
 7:  2001:978:3::26                                        4.563ms asymm  6 
 8:  adm-bb2-link.ip.twelve99.net                          4.097ms asymm  7 
 9:  no reply
10:  mno-b3-link.ip.twelve99.net                          29.967ms asymm  9 
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 AS204471 (KARSOLINK) · 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 / PTRRTTmtr lossASAS holder
1karsolink-01.net.karsolink.com
2a12:d8c0:105a:9001::1		0.4ms0%*AS204471KARSOLINK - 2S Computers SRL, IT
22a12:d8c0:109f:121::a10.4ms0%*AS204471KARSOLINK - 2S Computers SRL, IT
32a12:d8c0:101f:6::110.0ms20%AS204471KARSOLINK - 2S Computers SRL, IT
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Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.037ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.853ms 
 1:  karsolink-01.net.karsolink.com                        0.863ms 
 2:  2a12:d8c0:109f:121::a1                                0.888ms 
 3:  2a12:d8c0:101f:6::1                                  10.652ms 
 4:  no reply
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
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11:  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 SLO host (6connect)   transit only unreachable

filter likely at: past AS6939 (HURRICANE) · 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 / PTRRTTmtr lossASAS holder
1fw1-lju.6connect.com
2607:fae0:a000::2		0.3ms0%*AS80386CONNECT - 6connect, Inc., US
2*-0%*-
32a03:a100:0:201:1::10.6ms30%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
4e0-1.core1.lju1.he.net
2001:470:1:5be::1		2.2ms10%AS6939HURRICANE - Hurricane Electric LLC, US
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6port-channel1.core1.zag2.he.net
2001:470:0:2ea::2		3.9ms50%AS6939HURRICANE - Hurricane Electric LLC, US
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Rate-limited ICMPv6: hop 3, hop 4, hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.022ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.616ms 
 1:  fw1-lju.6connect.com                                  0.520ms 
 2:  no reply
 3:  no reply
 4:  e0-1.core1.lju1.he.net                                2.047ms 
 5:  no reply
 6:  port-channel1.core1.zag2.he.net                       4.120ms 
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
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14:  no reply
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18:  no reply
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20:  no reply
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24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500