AS198399 - FASTCON-AS FASTCON srlPARFC 4890 ✓RPKI ✓ 1/1ASPA -

AS overview

Test target: 2a00:c5e0::1 · static prefix probe · address space: PA · prefixes announced: 1

prefix(es): 2a00:c5e0::/32

MIX-IT / NAMEX / MINAP / TOP-IX / VSIX / EQUINIX-MILAN / BGPX-ROME / NAMEX-BARI / PCIX / DECIX-PALERMO peering

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

At least one router inside AS198399's announced prefix replied during the random-target probe. Hop(s): 2a00:c5e0:0:1::1, 2a00:c5e0::1. These are candidate targets for direct testing.

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 2026-09-23T12:01:15Z

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)

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

tracepath -6

 1?: [LOCALHOST]                        0.018ms pmtu 1500
 1:  _gateway                                              0.317ms 
 1:  _gateway                                              0.351ms 
 2:  sox-pn.sox.rs                                         0.477ms 
 3:  e0-33.core2.beg1.he.net                               1.254ms 
 4:  e0-34.core2.bts1.he.net                               8.665ms 
 5:  100ge0-0-0-2.core1.vie1.he.net                       10.897ms 
 6:  no reply
 7:  fastcon-v6.mix-it.net                                26.509ms asymm  5 
 8:  2a00:c5e0::1                                         30.242ms reached
     Resume: pmtu 1500 hops 8 back 6 

From DE host (Berlin)   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]                        0.020ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  1.541ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  1.959ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.963ms 
 3:  ae0-150.cr10.fra01.lwlcom.net                        10.154ms asymm  7 
 4:  ae0-20.cr10.fra07.lwlcom.net                         10.408ms asymm  6 
 5:  no reply
 6:  lo0.0.edge1.Milan1.level3.net                        24.108ms asymm  8 
 7:  2001:1900:5:2:2::64da                                26.536ms asymm 10 
 8:  2a02:7d8::2                                          22.044ms asymm 11 
 9:  2a02:7d8:0:f::ca                                     23.350ms asymm 10 
10:  2a00:c5e0::1                                         27.075ms reached
     Resume: pmtu 1500 hops 10 back 11 

From DE host (Düsseldorf)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.012ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.335ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.301ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.231ms 
 3:  no reply
 4:  lag30.core3-dus1.bb.wiit.network                      0.410ms 
 5:  lag0-vl1011.core1-fra-ix.bb.wiit.network              4.336ms 
 6:  lag0-vl1001.core1-nbg-ncd.bb.wiit.network             7.147ms 
 7:  lag0-vl6.core2-nbg-ncd.bb.wiit.network                7.211ms 
 8:  lag0-vl1006.core2-muc2.bb.wiit.network                9.623ms 
 9:  lag0-vl1009.core1-muc-eq3.bb.wiit.network             9.935ms 
10:  lag0-vl1001.core1-pda-vsix.bb.wiit.network           20.503ms 
11:  lag0-vl1001.core1-mil-mix.bb.wiit.network            20.344ms asymm  9 
12:  lag0-vl5.core3-mil-irid.bb.wiit.network              20.304ms asymm  8 
13:  fastcon.minap.it                                     20.481ms asymm  9 
14:  2a00:c5e0::1                                         24.651ms reached
     Resume: pmtu 1500 hops 14 back 10 

From NL host (go6lab)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.031ms pmtu 1500
 1:  2a00:8642:42::2                                       2.160ms 
 1:  2a00:8642:42::2                                       2.021ms 
 2:  gw.friends.steffann.nl                                2.293ms 
 3:  2a00:1ca8:1::194                                      4.671ms 
 4:  2a03:3f40::10:41                                      2.655ms 
 5:  2001:978:2:40::3:1                                    4.673ms 
 6:  be3458.ccr42.ams03.atlas.cogentco.com                 5.706ms 
 7:  be2950.ccr42.fra05.atlas.cogentco.com                15.747ms 
 8:  be7944.ccr22.muc03.atlas.cogentco.com                17.485ms 
 9:  port-channel5891.ccr91.mil02.atlas.cogentco.com      30.079ms 
10:  be2155.rcr71.vce01.atlas.cogentco.com                31.083ms 
11:  be2440.rcr51.rom01.atlas.cogentco.com                37.563ms 
12:  2001:978:2:11::b:2                                   36.609ms 
13:  no reply
14:  no reply
15:  no reply
16:  2a02:7d8::2                                          48.881ms 
17:  2a02:7d8:0:f::ca                                     38.155ms asymm  5 
18:  2a00:c5e0::1                                         38.575ms reached
     Resume: pmtu 1500 hops 18 back 6 

From ITA host (Karsolink)   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]                        0.037ms pmtu 1500
 1:  no reply
 2:  2a12:d8c0:109f:121::a1                                0.968ms 
 3:  2a12:d8c0:101f:103::1                                 9.065ms 
 4:  fastcon.minap.it                                     10.022ms 
 5:  2a00:c5e0::1                                         13.308ms reached
     Resume: pmtu 1500 hops 5 back 5 

From SLO host (6connect)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 4, hop 6 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.699ms 
 1:  fw1-lju.6connect.com                                  0.710ms 
 2:  no reply
 3:  2a03:a100:0:201:1::1                                  1.088ms 
 4:  2a03:a100:0:201:1::1                                  1.219ms pmtu 1500
 4:  e0-1.core1.lju1.he.net                                2.733ms 
 5:  no reply
 6:  port-channel1.core1.zag2.he.net                       4.491ms 
 7:  no reply
 8:  fastcon.minap.it                                     12.374ms 
 9:  2a00:c5e0::1                                         16.952ms reached
     Resume: pmtu 1500 hops 9 back 9 

From SLO host (T-2)   openRFC 4890 ✓

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

Path (traceroute + mtr + PTR)

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

tracepath -6

 1?: [LOCALHOST]                        0.032ms pmtu 1500
 1:  no reply
 2:  2a01:260:1::225                                       3.599ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        3.387ms 
 4:  2a01-260-1-1--39.core6.t-2.net                        2.331ms asymm  3 
 5:  hurricane-electric.nikhef.nlsix.net                  39.636ms asymm  4 
 6:  be7.core2.fra2.he.net                                38.378ms asymm  5 
 7:  be3.core4.fra1.he.net                                49.114ms 
 8:  be1.core1.mil2.he.net                                34.856ms asymm  7 
 9:  be1.core1.mil2.he.net                                35.432ms asymm  7 
10:  no reply
11:  fastcon-v6.mix-it.net                                31.951ms asymm  7 
12:  2a00:c5e0::1                                         42.699ms reached
     Resume: pmtu 1500 hops 12 back 8