AS200553 - interfibra Interfibra S.R.LPARPKI -ASPA -

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IPv6 prefix announced, but nothing inside is responding yet. AS200553 announces 2 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: 2a06:3680::1 · (no live host found) · address space: PA · prefixes announced: 2

prefix(es): 2a06:3680::/29, 2a0a:d640::/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 2020-03-23. IPv6 LAN: 2001:7f8:b:100:1d1:a520:553:80. Locations: -.

RPKI & ASPA

0 of 2 prefix(es) covered by a valid ROA, 2 not-found.

PrefixRPKI stateReasonCovering VRP(s)
2a06:3680::/29- not-foundno covering VRP
2a0a:d640::/29- not-foundno covering VRP

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

We probed 30 arbitrary IPv6 address(es) inside AS200553's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:470:0:2ea::2 at hop 6 - that router answers ICMPv6 Echo. This is not in AS200553'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 2026-05-25T12:33:46Z

Failure detail — what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
go6lab2a00:8642:42::752a06:3680::1icmp6-echono_echo2026-05-25T12:33:46Z
karsolink2a12:d8c0:105a:9001::a1542a06:3680::1icmp6-echono_echo2026-05-25T12:42:01Z
odin2607:fae0:a000::422a06:3680::1icmp6-echono_echo2026-05-25T12:33:24Z

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: past AS41327 (FIBERTELECOM-AS) · 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::31.7ms0%AS203993STEFFANN-DC-AS - S.J.M. Steffann, NL
2*-0%*-
3speed-ix.fibertelecom.it
2001:7f8:b7::a504:1327:1		3.3ms0%-NA
42a03:b020::22619.0ms0%AS41327FIBERTELECOM-AS - Fiber Telecom S.p.A., IT
5*---
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tracepath -6

 1?: [LOCALHOST]                        0.044ms pmtu 1500
 1:  2a00:8642:42::3                                       1.747ms 
 1:  2a00:8642:42::3                                       1.483ms 
 2:  no reply
 3:  speed-ix.fibertelecom.it                              4.095ms 
 4:  2a03:b020::226                                       19.791ms 
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
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20:  no reply
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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
1*-0%*-
22a12:d8c0:109f:121::a10.4ms-AS204471KARSOLINK - 2S Computers SRL, IT
32a12:d8c0:101f:103::18.5ms20%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]                        0.029ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  2a12:d8c0:101f:103::1                                 8.988ms 
 4:  no reply
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
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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		0.4ms0%*AS80386CONNECT - 6connect, Inc., US
2*-0%*-
32a03:a100:0:201:1::10.7ms20%AS56635XENYA - XENYA inzeniring, proizvodnja in trgovina, d.o.o. Ljubljana, SI
4*-0%-
5*---
6port-channel1.core1.zag2.he.net
2001:470:0:2ea::2		3.8ms0%AS6939HURRICANE - Hurricane Electric LLC, US
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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]                        0.029ms pmtu 1500
 1:  fw1-lju.6connect.com                                  0.523ms 
 1:  fw1-lju.6connect.com                                  0.357ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    0.900ms 
 3:  2a03:a100:0:201:1::1                                  0.898ms 
 4:  e0-1.core1.lju1.he.net                                2.064ms 
 5:  no reply
 6:  port-channel1.core1.zag2.he.net                       4.018ms 
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
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24:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500