AS203358 - INCOS-Stueckler Guenther StuecklerPARFC 4890 ✓RPKI ✓ 1/1ASPA -

AS overview

Test target: 2a12:c140::1 · static prefix probe · address space: PA · prefixes announced: 1

prefix(es): 2a12:c140::/29

VIX / AAIX / SAIX / TIROL-IX / ERA-IX peering

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

We probed 35 arbitrary IPv6 address(es) inside AS203358's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a00:a6a0:1:1::22:2 at hop 21 - that router answers ICMPv6 Echo. This is not in AS203358'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 honored. Forged ICMPv6 PTB (MTU=1280) was accepted by the destination's stack: the next 1500-byte Echo Reply arrived split into 2 fragments via the IPv6 Fragment Header.
method: ICMPv6 Echo + forged PTB, tested 2026-09-23T13:37:45Z

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)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.016ms pmtu 1500
 1:  _gateway                                              0.627ms 
 1:  _gateway                                              0.631ms 
 2:  sox-pn.sox.rs                                         0.444ms 
 3:  2001:7f8:1e:8::3d                                     0.529ms asymm  2 
 4:  ae8-930.RT.IRX.VIE.AT.retn.net                       11.290ms asymm  3 
 5:  GW-AS8075.retn.net                                   14.602ms asymm  4 
 6:  2a0b:6c40:0:95:185:211:219:43                        13.162ms asymm  4 
 7:  2a12:c140::1                                         14.467ms reached
     Resume: pmtu 1500 hops 7 back 5 

From DE host (Berlin)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.023ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.595ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.459ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.956ms 
 3:  ae3-90.cr10.ham01.lwlcom.net                          5.342ms 
 4:  ae0-50.cr11.ham01.lwlcom.net                          5.134ms 
 5:  2a00:c380:f000::4b                                    5.791ms asymm  4 
 6:  ae4-2087.dus10.core-backbone.com                     11.570ms asymm  5 
 7:  ae43-2026.fra30.core-backbone.com                    11.547ms asymm  5 
 8:  ae16-2123.fra40.core-backbone.com                    11.794ms asymm  6 
 9:  ae8-2027.muc10.core-backbone.com                     15.561ms asymm  8 
10:  ae1-2030.muc20.core-backbone.com                     15.571ms asymm  7 
11:  ae4-2057.slz10.core-backbone.com                     17.496ms asymm  8 
12:  ae2-2058.vie20.core-backbone.com                     20.999ms asymm  9 
13:  2a01:4a0:1338:188::2                                 25.089ms asymm  9 
14:  2a0b:6c40:0:95:185:211:219:43                        21.858ms asymm  6 
15:  2a12:c140::1                                         25.256ms reached
     Resume: pmtu 1500 hops 15 back 7 

From DE host (Düsseldorf)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.030ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.390ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.316ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.169ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.403ms 
 5:  lag2.core1-dus-ix.bb.wiit.network                     0.569ms 
 6:  de-cix.fra.ama-networx.net                            4.145ms 
 7:  2a0b:6c40:0:146:185:211:216:41                       15.040ms asymm  9 
 8:  2a0b:6c40:0:95:185:211:219:43                        20.348ms asymm  7 
 9:  2a12:c140::1                                         22.975ms reached
     Resume: pmtu 1500 hops 9 back 8 

From NL host (go6lab)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.055ms pmtu 1500
 1:  2a00:8642:42::2                                       3.680ms 
 1:  2a00:8642:42::2                                       5.133ms 
 2:  no reply
 3:  2a00:1ca8:1::194                                      3.526ms 
 4:  2a03:3f40::10:33                                      6.188ms 
 5:  ams-ix.retn.net                                       6.200ms asymm  7 
 6:  RT.IRX.VIE.AT.retn.net                               21.723ms 
 7:  GW-AS8075.retn.net                                   22.686ms asymm  6 
 8:  2a0b:6c40:0:95:185:211:219:43                        22.110ms 
 9:  2a12:c140::1                                         26.125ms reached
     Resume: pmtu 1500 hops 9 back 9 

From ITA host (Karsolink)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.026ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.792ms 
 1:  karsolink-01.net.karsolink.com                        0.579ms 
 2:  2a12:d8c0:109f:121::a1                                0.633ms 
 3:  2a12:d8c0:101f:6::1                                  10.251ms 
 4:  no reply
 5:  100ge0-0-0-20.core1.vie1.he.net                      21.871ms 
 6:  2001:470:26b::2                                      32.072ms asymm  7 
 7:  2a0b:6c40:0:95:185:211:219:43                        16.789ms 
 8:  2a12:c140::1                                         19.399ms reached
     Resume: pmtu 1500 hops 8 back 8 

From SLO host (6connect)   openRFC 4890 ✓

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

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]                        0.025ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.602ms 
 1:  fw1-lju.6connect.com                                  0.467ms 
 2:  no reply
 3:  no reply
 4:  2a00:ee0:1:15::2                                      1.839ms asymm  3 
 5:  2a00:ee0:1:15::2                                     62.401ms pmtu 1500
 5:  2a11:4142:2002::                                      1.139ms asymm  6 
 6:  r2-vie1-at.as5405.net                                 7.292ms asymm  8 
 7:  et9-4096.r2-vie2-at.as5405.net                        7.178ms asymm  8 
 8:  vix.ip6.core.xinon.at                                 8.427ms asymm  5 
 9:  2a12:c140::1                                         11.441ms reached
     Resume: pmtu 1500 hops 9 back 7 

From SLO host (T-2)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.025ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.931ms 
 1:  no reply
 2:  2a01:260:1::225                                       6.255ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        2.529ms 
 4:  no reply
 5:  100ge0-0-0-31.core1.vie1.he.net                      14.026ms 
 6:  2001:470:26b::3                                      10.770ms 
 7:  2a0b:6c40:0:95:185:211:219:43                        10.384ms asymm  6 
 8:  2a0b:6c40:0:95:185:211:219:43                        10.159ms asymm  6 
 9:  2a12:c140::1                                         13.687ms reached
     Resume: pmtu 1500 hops 9 back 7