AS8387 - T-SYSTEMS-AT Deutsche Telekom Global Business SolutionsPI/PARFC 4890 ✓RPKI ✓ 3/3ASPA -

AS overview

Test target: 2001:9d0::2 · static prefix probe · address space: mixed · prefixes announced: 3

prefix(es): 2001:678:554::/48, 2001:678:5a8::/48, 2001:9d0::/32

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

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

We probed 70 arbitrary IPv6 address(es) inside AS8387's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:7f8:30:0:1:1:0:8387 at hop 23 - that router answers ICMPv6 Echo. This is not in AS8387'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 2026-09-22T13:50:52Z

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]                        0.044ms pmtu 1500
 1:  _gateway                                              1.069ms 
 1:  _gateway                                              2.393ms 
 2:  sox-pn.sox.rs                                         2.846ms 
 3:  2001:7f8:1e:8::3d                                     2.174ms asymm  2 
 4:  ae8-930.RT.IRX.VIE.AT.retn.net                       12.825ms asymm  3 
 5:  2001:7f8:30:0:2:1:0:8387                             12.057ms asymm  4 
 6:  r1-1060ai-p10-400.net.t-systems.at                   13.814ms reached
     Resume: pmtu 1500 hops 6 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]                        0.025ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.707ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.548ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.897ms 
 3:  ae0-40.cr10.muc02.lwlcom.net                         11.985ms 
 4:  ae0-10.cr10.muc01.lwlcom.net                         12.387ms 
 5:  2001:7f8:30:0:1:1:0:8387                             52.136ms reached
     Resume: pmtu 1500 hops 5 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]                        0.023ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.684ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  1.006ms 
 2:  ae0-101.cr10.dus02.lwlcom.net                         0.564ms 
 3:  ae0-20.cr10.dus01.lwlcom.net                          1.016ms 
 4:  ae0-20.cr10.vel01.lwlcom.net                          1.312ms 
 5:  ae0-10.cr10.dus06.lwlcom.net                          0.940ms 
 6:  ae0-40.cr10.fra06.lwlcom.net                          4.120ms 
 7:  ae0-20.cr10.muc01.lwlcom.net                         14.477ms asymm  5 
 8:  2001:7f8:30:0:1:1:0:8387                             16.405ms reached
     Resume: pmtu 1500 hops 8 back 6 

From NL host (go6lab)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.032ms pmtu 1500
 1:  2a00:8642:42::2                                       3.333ms 
 1:  2a00:8642:42::2                                       3.414ms 
 2:  gw.friends.steffann.nl                                4.782ms 
 3:  speed-ix.he.net                                      12.436ms 
 4:  be2.core4.fra1.he.net                                12.807ms 
 5:  be8.core1.prg1.he.net                                19.293ms 
 6:  be3.core1.vie1.he.net                                24.117ms 
 7:  2001:7f8:30:0:2:1:0:8387                             24.826ms 
 8:  2001:7f8:30:0:1:1:0:8387                             25.172ms reached
     Resume: pmtu 1500 hops 8 back 8 

From ITA host (Karsolink)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.031ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        1.523ms 
 1:  karsolink-01.net.karsolink.com                        1.273ms 
 2:  2a12:d8c0:109f:121::a1                                1.364ms 
 3:  2a12:d8c0:101f:103::1                                 9.393ms 
 4:  no reply
 5:  100ge0-0-0-20.core1.vie1.he.net                      24.112ms 
 6:  2001:7f8:30:0:1:1:0:8387                             16.979ms reached
     Resume: pmtu 1500 hops 6 back 7 

From SLO host (6connect)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.033ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.661ms 
 1:  fw1-lju.6connect.com                                  0.662ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    0.976ms 
 3:  2a03:a100:0:201:1::1                                  1.217ms 
 4:  2a03:a100:0:201:1::1                                  0.972ms pmtu 1500
 4:  e0-1.core1.lju1.he.net                                2.157ms 
 5:  100ge0-0-0-5.core1.vie1.he.net                       10.376ms 
 6:  2001:7f8:30:0:1:1:0:8387                              8.388ms reached
     Resume: pmtu 1500 hops 6 back 10 

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]                        0.023ms pmtu 1500
 1:  2a01:261:313:b814::1                                  1.066ms 
 1:  no reply
 2:  2a01:260:1::225                                      12.912ms 
 3:  2a01-260-1-1--9a.core6.t-2.net                        3.017ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        2.316ms asymm  3 
 5:  100ge0-0-0-31.core1.vie1.he.net                      12.845ms 
 6:  2001:7f8:30:0:1:1:0:8387                             53.717ms reached
     Resume: pmtu 1500 hops 6 back 6