AS5603 - Telekom SlovenijePI/PARPKI ⚠ 11/12ASPA -

AS overview

Test target: 2a00:ee0:d::13 · ns3.siol.net · address space: mixed · prefixes announced: 12

prefix(es): 2a00:ee4::/32, 2a00:ee0::/32, 2a02:e20::/29, 2a00:ee6::/32, 2a00:ee5::/32, 2a00:ee0::/29, 2a00:ee1::/32, 2001:67c:20d8::/48 (+4 more)

SIX peering

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

At least one router inside AS5603's announced prefix replied during the random-target probe. Hop(s): 2a00:ee1:800:9::1. These are candidate targets for direct testing.

ICMPv6 Type 2 (Packet Too Big) acceptance - active test

Type 2 active test inconclusive: no Echo Reply after PTB (probe 1500B).
method: ICMPv6 Echo + forged PTB, tested 2026-09-23T10:33:50Z

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)'

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 ↗

• ● SRB host (SOX, Belgrade)
• ● DE host (Berlin)
• ● DE host (Düsseldorf)
• ● NL host (go6lab)
• ● ITA host (Karsolink)
• ● SLO host (6connect)
• ● SLO host (T-2)
• ── solid line = echo reply, PTB honored (clean reach)
• — — dashed line = echo reply but PTB not honored (RFC 4890 violation)
• no line = no echo reply (never reached)
• ◉ target: green = clean, amber = reachable-but-violation / unreachable
• ⚠ suspected drop AS
• ⋯ silent (unanswered) hops
• ● IXP hop

From SRB host (SOX, Belgrade)   open

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.010ms pmtu 1500
 1:  _gateway                                              0.865ms 
 1:  _gateway                                              1.443ms 
 2:  2001:7f8:1e::4                                        0.885ms 
 3:  ts6-vix-mb.telekom.si                                27.947ms asymm  6 
 4:  taurus-3.siol.net                                    27.981ms reached
     Resume: pmtu 1500 hops 4 back 7 

From DE host (Berlin)   open

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  1.071ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  1.029ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        1.206ms 
 3:  ae0-10.cr10.ber03.lwlcom.net                          1.329ms 
 4:  ae0-15.cr11.dtm01.lwlcom.net                          9.741ms asymm  5 
 5:  ae0-20.cr10.dtm01.lwlcom.net                          8.946ms asymm  4 
 6:  ae0-50.cr10.dus02.lwlcom.net                          9.135ms asymm  3 
 7:  ae0-10.cr10.dus01.lwlcom.net                          9.501ms asymm  4 
 8:  ae6-60.cr10.ams01.lwlcom.net                         12.399ms asymm  5 
 9:  as5405.frys-ix.net                                   11.858ms 
10:  r7-ams1-nl.as5405.net                                32.447ms asymm 13 
11:  r7-fra1-de.as5405.net                                32.103ms asymm 12 
12:  r5-fra1-de.as5405.net                                32.427ms asymm 11 
13:  r2-vie1-at.as5405.net                                32.475ms asymm 10 
14:  r1-lju1-si.as5405.net                                32.206ms asymm  9 
15:  2a11:4142:2002::1                                    29.710ms asymm  7 
16:  taurus-3.siol.net                                    30.264ms reached
     Resume: pmtu 1500 hops 16 back 9 

From DE host (Düsseldorf)   open

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.029ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.712ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.660ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.351ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.476ms 
 5:  lag8.core1-dus-ix.bb.wiit.network                     0.515ms 
 6:  slovenije6.telekom.si                                14.061ms 
 7:  taurus-3.siol.net                                    14.616ms reached
     Resume: pmtu 1500 hops 7 back 8 

From NL host (go6lab)   open

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  ???                                                   5.123ms 
 1:  ???                                                 346.614ms 
 2:  no reply
 3:  speed-ix.inter.link                                   3.544ms asymm  4 
 4:  r5-ams1-nl.as5405.net                                30.506ms asymm 15 
 5:  r7-ams1-nl.as5405.net                                31.552ms asymm 14 
 6:  r7-fra1-de.as5405.net                                28.873ms asymm 13 
 7:  r5-fra1-de.as5405.net                                31.312ms asymm 12 
 8:  r2-vie1-at.as5405.net                                28.868ms asymm 11 
 9:  r1-lju1-si.as5405.net                                28.512ms asymm 10 
10:  2a11:4142:2002::1                                    29.344ms 
11:  taurus-3.siol.net                                    30.382ms reached
     Resume: pmtu 1500 hops 11 back 12 

From ITA host (Karsolink)   open

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  no reply
 2:  no reply
 3:  2a12:d8c0:101f:103::1                                 8.879ms 
 4:  interlink-as5405.mix-it.net                           8.876ms asymm  5 
 5:  r1-lju1-si.as5405.net                                16.086ms asymm  6 
 6:  2a11:4142:2002::1                                    20.942ms 
 7:  taurus-3.siol.net                                   325.307ms reached
     Resume: pmtu 1500 hops 7 back 8 

From SLO host (6connect)   open

filter likely at: (none) · min PMTU on path: 9000

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.829ms 
 1:  fw1-lju.6connect.com                                  0.693ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    1.140ms 
 3:  2a00:ee1:800:9::1                                     2.253ms 
 4:  no reply
 5:  no reply
 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
15:  no reply
16:  no reply
17:  no reply
18:  no reply
19:  no reply
20:  no reply
21:  no reply
22:  no reply
     Too many hops: pmtu 9000
     Resume: pmtu 9000 

From SLO host (T-2)   open

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.042ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       4.572ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        3.460ms 
 4:  2001:7f8:46:0:1::5603                                 3.865ms 
 5:  taurus-3.siol.net                                     4.030ms reached
     Resume: pmtu 1500 hops 5 back 6