AS57142 - AS-FIBER23 Fiber 23 SRLRPKI ✓ 1/1ASPA -

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AS overview

Test target: 2a13:9500:b8::1 · static prefix probe · address space: unknown · prefixes announced: 1

prefix(es): 2a13:9500:b8::/48

Targets & per-vantage-point probe results (1 target(s) across 7 vantage point(s))

Source codes (hover any badge for full description): CUR=curated · NS/SOA/MX=DNS records · SPF=SPF TXT · DRV=holder-derived (www, ns1, mail, gw, …) · ATL=RIPE Atlas · PDB=PeeringDB · WHOIS=RIPE whois · RDAP=RIPE RDAP · HIT=IPv6 Hitlist · RTR=in-prefix path hop (router) · PRB=static prefix probe · SYN=synthetic prefix::1 fallback

Target IP / hostnameSourceSRB host (SOX, Belgrade)DE host (Berlin)DE host (Düsseldorf)NL host (go6lab)ITA host (Karsolink)SLO host (6connect)SLO host (T-2)
ping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reachedping1500B:80:443reached
2a13:9500:b8::1prb??-??-??-??-??-??-??-

RPKI & ASPA

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

PrefixRPKI stateReasonCovering VRP(s)
2a13:9500:b8::/48✓ validmatched VRP (correct origin, length within maxLength)AS57142 /48 maxLen 48 (ripe)

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

We probed 35 arbitrary IPv6 address(es) inside AS57142's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a02:2d8:4:2806:232a::1 at hop 8 - that router answers ICMPv6 Echo. This is not in AS57142'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 2026-09-23T12:09:33Z

Failure detail - what to grep in your logs
vantageour sourceyour targetmethodresulttested (UTC)
belgrade2a09:ab81::912a13:9500:b8::1icmp6-echono_echo2026-09-23T12:09:33Z
berlin2a06:d1c1:10b::cccc2a13:9500:b8::1icmp6-echono_echo2026-09-23T12:09:32Z
duseldorf2a06:d1c1:10d::aaaa2a13:9500:b8::1icmp6-echono_echo2026-09-23T12:09:30Z
go6lab2a00:8642:42::752a13:9500:b8::1icmp6-echono_echo2026-09-23T12:11:25Z
karsolink2a12:d8c0:105a:9001::a1542a13:9500:b8::1icmp6-echono_echo2026-09-23T12:09:29Z
odin2607:fae0:a000::422a13:9500:b8::1icmp6-echono_echo2026-09-23T12:09:30Z
t22a01:261:313:b814:2a0:98ff:fe5b:13e42a13:9500:b8::1icmp6-echono_echo2026-09-23T12:09:32Z

Attempt log (belgrade):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (berlin):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (duseldorf):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (go6lab):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (karsolink):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (odin):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_tcp: tcp/80 not open

Attempt log (t2):

  1. icmp6-echono_echo: no Echo Reply to 1300-byte probe
  2. dns-tcpno_tcp: connect failed: timed out
  3. tlsno_tcp: TLS connect failed
  4. httpno_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 2a01:261:313:b814:2a0:98ff:fe5b:13e4 or src host 2a06:d1c1:10b::cccc or src host 2a06:d1c1:10d::aaaa or src host 2a09:ab81::91 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 some of our source IPs but not others, the drop is path-asymmetric - at least one transit on the differing route is filtering.

Multi-vantage path map

Every hop of all vantages’ traceroutes toward the target, drawn left→right, grouped into per-AS bubbles (a hop seen from several vantages is one shared bubble, so converging paths merge). It answers two questions per vantage — shown on each source bubble as echo ✓/⚠/✗ · trace ✓/✗: did the destination reply to ICMPv6 Echo (✓ honored, ⚠ replied but PTB not honored, ✗ no reply), and did the traceroute reach it. A line to the target is drawn only when that vantage got an echo reply — solid if the PTB was honored, dashed if not (reachable but a broken-PMTUD / RFC 4890 violation). The path depth still shows how far the traceroute itself got, and runs of unanswered (* *) hops collapse into one dashed “silent” bubble. Open full size ↗

multi-vantage path diagram for AS57142

From SRB host (SOX, Belgrade)   all blocked

filter likely at: past AS9002 (RETN-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
12a09:ab81::10.3ms0%*AS60733PERKE-NET - ZORAN PEROVIC trading as Agencija Perke.NET, RS
22001:7f8:1e::40.5ms0%AS13004SOX - Serbian Open Exchange DOO, RS
32001:7f8:30:0:2:1:0:900212.7ms0%-NA
4RT.NMX.ROM.IT.retn.net
2a02:2d8::57f5:e08f
27.4ms0%AS9002RETN-AS - RETN Limited, GB
5GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
29.7ms0%AS9002RETN-AS - RETN Limited, GB
6*---
7*---
8*---
9*---
10*---
11*---
12*---
13*---
14*---

tracepath -6

 1?: [LOCALHOST]                        0.013ms pmtu 1500
 1:  _gateway                                              0.616ms 
 1:  _gateway                                              0.482ms 
 2:  2001:7f8:1e::4                                        0.619ms 
 3:  2001:7f8:30:0:2:1:0:9002                             12.886ms 
 4:  RT.NMX.ROM.IT.retn.net                               27.483ms 
 5:  GW-AS210917.retn.net                                 29.866ms 
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From DE host (Berlin)   all blocked

filter likely at: past AS9002 (RETN-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
1xe-0-0-13-178.gw01.ber01.as59645.net
2a06:d1c1:100:b::1
0.3ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2ae0-2453.cr10.ber01.lwlcom.net
2a06:d1c0::dead:beef:1c02
0.5ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
3retn.bcix.de
2001:7f8:19:1::232a:1
10.3ms0%-NA
4RT.NMX.ROM.IT.retn.net
2a02:2d8::57f5:e08f
29.4ms0%AS9002RETN-AS - RETN Limited, GB
5GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
73.6ms0%AS9002RETN-AS - RETN Limited, GB
6*---
7*---
8*---
9*---
10*---
11*---
12*---
13*---
14*---

tracepath -6

 1?: [LOCALHOST]                        0.025ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.521ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.505ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        1.049ms 
 3:  retn.bcix.de                                         28.518ms asymm  5 
 4:  RT.NMX.ROM.IT.retn.net                               29.320ms asymm  5 
 5:  GW-AS210917.retn.net                                 31.949ms asymm  6 
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From DE host (Düsseldorf)   all blocked

filter likely at: past AS9002 (RETN-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
1xe-0-0-12-142.gw01.dus01.as59645.net
2a06:d1c1:100:d::1
0.2ms0%*AS59645WYBT-NET - Tobias Fiebig, DE
2eth1-0-12-h5594.edge5-dus1.bb.wiit.network
2001:4ba0:92f4:3::1
1.0ms0%AS24961MYLOC-AS - WIIT AG, DE
3*-0%-
4lag11.core3-dus1.bb.wiit.network
2001:4ba0:ffe9:115::3
0.2ms0%AS24961MYLOC-AS - WIIT AG, DE
5lag2.core1-dus-ix.bb.wiit.network
2001:4ba0:ffe9:4f::1
0.5ms0%AS24961MYLOC-AS - WIIT AG, DE
6de-cix1.rt.act.fkt.de.retn.net
2001:7f8::232a:0:1
4.3ms0%-NA
7RT.NMX.ROM.IT.retn.net
2a02:2d8::57f5:e08f
23.0ms0%AS9002RETN-AS - RETN Limited, GB
8GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
29.2ms0%AS9002RETN-AS - RETN Limited, GB
9*---
10*---
11*---
12*---
13*---
14*---

tracepath -6

 1?: [LOCALHOST]                        0.019ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.426ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.358ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.337ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.531ms 
 5:  lag8.core1-dus-ix.bb.wiit.network                     0.567ms 
 6:  de-cix1.rt.act.fkt.de.retn.net                        4.451ms asymm  4 
 7:  RT.NMX.ROM.IT.retn.net                               22.895ms asymm  4 
 8:  GW-AS210917.retn.net                                 36.592ms asymm  5 
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From NL host (go6lab)   all blocked

filter likely at: past AS9002 (RETN-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::21.0ms0%AS203993GNA-DC1-AS - S.J.M. Steffann, NL
2*-0%*-
32a00:1ca8:1::1942.9ms0%AS50673Serverius-as - Serverius Holding B.V., NL
42a03:3f40::10:335.1ms0%AS50673Serverius-as - Serverius Holding B.V., NL
5ams-ix.retn.net
2001:7f8:1::a500:9002:1
6.4ms0%-NA
6RT.NMX.ROM.IT.retn.net
2a02:2d8::57f5:e08f
30.1ms0%AS9002RETN-AS - RETN Limited, GB
7GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
33.3ms0%AS9002RETN-AS - RETN Limited, GB
8*---
9*---
10*---
11*---
12*---
13*---
14*---

tracepath -6

 1?: [LOCALHOST]                        0.127ms pmtu 1500
 1:  2a00:8642:42::2                                       2.444ms 
 1:  2a00:8642:42::2                                       1.704ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      5.150ms 
 4:  2a03:3f40::10:33                                      9.889ms 
 5:  ams-ix.retn.net                                       6.293ms asymm  7 
 6:  RT.NMX.ROM.IT.retn.net                               31.329ms 
 7:  GW-AS210917.retn.net                                 36.436ms 
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From ITA host (Karsolink)   all blocked

filter likely at: past AS9002 (RETN-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
1*-0%*-
22a12:d8c0:109f:121::a10.3ms0%*AS204471KARSOLINK - 2S Computers SRL, IT
32a12:d8c0:109f:106::a23.2ms30%AS204471KARSOLINK - 2S Computers SRL, IT
42a02:2d8:4:1815:232a27.4ms0%-
5RT.NMX.ROM.IT.retn.net
2a02:2d8::57f5:e08f
10.1ms0%AS9002RETN-AS - RETN Limited, GB
6GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
37.9ms0%AS9002RETN-AS - RETN Limited, GB
7*---
8*---
9*---
10*---
11*---
12*---
13*---
14*---

Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.032ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.695ms 
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                                0.683ms 
 3:  2a12:d8c0:109f:106::a2                                3.667ms 
 4:  ae8-202.RT.CLR.MIL.IT.retn.net                        8.165ms asymm  5 
 5:  RT.NMX.ROM.IT.retn.net                               15.077ms 
 6:  GW-AS210917.retn.net                                 58.393ms 
 7:  no reply
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500 

From SLO host (6connect)   all blocked

filter likely at: past AS9002 (RETN-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
1fw1-lju.6connect.com
2607:fae0:a000::2
0.4ms0%*AS80386CONNECT - 6connect, Inc., US
2*---
3*-40%-
42a00:ee0:1:15::21.3ms0%AS5603SIOL-NET - Telekom Slovenije, d.d., SI
5de-cix1.rt.act.fkt.de.retn.net
2001:7f8::232a:0:1
14.0ms0%-NA
6RT.NMX.ROM.IT.retn.net
2a02:2d8::57f5:e08f
26.1ms0%AS9002RETN-AS - RETN Limited, GB
7GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
203.2ms0%AS9002RETN-AS - RETN Limited, GB
8*---
9*---
10*---
11*---
12*---
13*---
14*---

Rate-limited ICMPv6: hop 3 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.018ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.869ms 
 1:  fw1-lju.6connect.com                                  0.521ms 
 2:  no reply
 3:  2a00:ee1:800:9::1                                     2.582ms 
 4:  2a00:ee0:1:15::2                                      1.552ms asymm  3 
 5:  2a00:ee0:1:15::2                                      1.535ms pmtu 1500
 5:  de-cix1.rt.act.fkt.de.retn.net                       15.773ms asymm  9 
 6:  RT.NMX.ROM.IT.retn.net                               26.052ms asymm  9 
 7:  GW-AS210917.retn.net                                 28.113ms asymm 10 
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500

From SLO host (T-2)   all blocked

filter likely at: past AS9002 (RETN-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
12a01:261:313:b814::10.5ms0%*AS34779T-2-AS - T-2, d.o.o., SI
22a01:260:1::2252.9ms0%*AS34779T-2-AS - T-2, d.o.o., SI
32a01-260-1-1--9a.core6.t-2.net
2a01:260:1:1::9a
2.5ms0%*AS34779T-2-AS - T-2, d.o.o., SI
42a01-260-1-1--c.core6.t-2.net
2a01:260:1:1::c
4.2ms0%*AS34779T-2-AS - T-2, d.o.o., SI
52001:7f8:30:0:2:1:0:90027.7ms0%*-NA
62001:7f8:30:0:2:1:0:90028.5ms0%-NA
7GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
29.1ms0%AS9002RETN-AS - RETN Limited, GB
8GW-AS210917.retn.net
2a02:2d8:4:2806:232a::1
28.8ms0%AS9002RETN-AS - RETN Limited, GB
9*---
10*---
11*---
12*---
13*---
14*---

tracepath -6

 1?: [LOCALHOST]                        0.031ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       5.143ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        2.635ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        2.422ms asymm  3 
 5:  2001:7f8:30:0:2:1:0:9002                              8.258ms 
 6:  2001:7f8:30:0:2:1:0:9002                              9.580ms asymm  5 
 7:  GW-AS210917.retn.net                                 25.811ms 
 8:  GW-AS210917.retn.net                                 31.579ms asymm  7 
 9:  no reply
10:  no reply
11:  no reply
12:  no reply
13:  no reply
14:  no reply
     Too many hops: pmtu 1500
     Resume: pmtu 1500